Growth Performance, Welfare and Behavior Indicators in Post-Weaning Piglets Fed Diets Supplemented with Different Levels of Bakery Meal Derived from Food By-Products

Abstract

This study aimed to evaluate the effect of different levels (15% and 20% w.w⁻¹) of bakery meal (BM) inclusion on growth performance, welfare and behavior indicators in post-weaning piglets. Sixty post-weaning castrated male piglets were selected and divided in 3 feeding treatments: standard post-weaning diet with no BM added (CON), standard post-weaning diet with 15% w.w⁻¹ BM added (BM 15) and standard post-weaning diet with 20% w.w⁻¹ BM added (BM 20). Body weight (BW), average daily gain (ADG), feed intake (FI) and feed conversion ratio (FCR) were recorded individually on a weekly basis. Additionally, welfare, quality behavior indicators, wounds and tail-biting incidence were assessed. The supplementation with BM in piglets’ diet had a significant impact on ADG and FCR during certain periods of the trial. BM 15 piglets showed higher ADG and lower FCR in the last week of the experiment compared to CON piglets (1278.57 ± 7.14 g vs. 905.00 ± 47.86 g and 1.69 ± 0.04 g vs. 2.35 ± 0.08 g, respectively). Overall, BM inclusion had no significant effect on performance, quality behavior characteristics and welfare (p > 0.05). The inclusion of BM at either 15% or 20% w.w⁻¹ illustrated no detrimental effects on the overall growth parameters, welfare and behavior indicators for post-weaned piglets.

Full text

Citation: Termatzidou, S.-A.;
Dedousi, A.; Kritsa, M.-Z.; Banias,
G.F.; Patsios, S.I.; Sossidou, E.N.
Growth Performance, Welfare and
Behavior Indicators in Post-Weaning
Piglets Fed Diets Supplemented with
Different Levels of Bakery Meal
Derived from Food By-Products.
Sustainability 2023,15, 12827.
https://doi.org/10.3390/
su151712827
Academic Editor: Dario Donno
Received: 3 August 2023
Revised: 21 August 2023
Accepted: 22 August 2023
Published: 24 August 2023
Copyright: © 2023 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
sustainability
Article
Growth Performance, Welfare and Behavior Indicators in
Post-Weaning Piglets Fed Diets Supplemented with Different
Levels of Bakery Meal Derived from Food By-Products
Sofia-Afroditi Termatzidou 1,* , Anna Dedousi 1, Maria-Zoi Kritsa 1, George F. Banias 2, Sotiris I. Patsios 2
and Evangelia N. Sossidou 1
1Veterinary Research Institute, Ellinikos Georgikos Organismos—DIMITRA, ELGO-DIMITRA Campus,
570 01 Thermi, Greece; dedousi@vri.gr (A.D.); mzkritsa@gmail.com (M.-Z.K.); sossidou@vri.gr (E.N.S.)
2
Institute for Bio-Economy and Agri-Technology (IBO), Centre for Research and Technology-Hellas (CERTH),
570 01 Thessaloniki, Greece; g.banias@certh.gr (G.F.B.); patsios@certh.gr (S.I.P.)
*Correspondence: termatzidou@heliadesvet.com
Abstract:
This study aimed to evaluate the effect of different levels (15% and 20% w.w
−1
) of bakery
meal (BM) inclusion on growth performance, welfare and behavior indicators in post-weaning piglets.
Sixty post-weaning castrated male piglets were selected and divided in 3 feeding treatments: standard
post-weaning diet with no BM added (CON), standard post-weaning diet with
15% w.w−1BM
added
(BM 15) and standard post-weaning diet with 20% w.w
−1
BM added (BM 20). Body weight (BW),
average daily gain (ADG), feed intake (FI) and feed conversion ratio (FCR) were recorded individually
on a weekly basis. Additionally, welfare, quality behavior indicators, wounds and tail-biting incidence
were assessed. The supplementation with BM in piglets’ diet had a significant impact on ADG and
FCR during certain periods of the trial. BM 15 piglets showed higher ADG and lower FCR in the
last week of the experiment compared to CON piglets (1278.57
±
7.14 g vs. 905.00
±
47.86 g and
1.69 ±0.04 g
vs. 2.35
±
0.08 g, respectively). Overall, BM inclusion had no significant effect on
performance, quality behavior characteristics and welfare (p> 0.05). The inclusion of BM at either
15% or 20% w.w
−1
illustrated no detrimental effects on the overall growth parameters, welfare and
behavior indicators for post-weaned piglets.
Keywords: bakery meal; post-weaning piglets; performance; behavior; welfare
1. Introduction
Feed cost constitutes up to 85% of the total production costs of a livestock farm [
1
].
More specifically, feed cost accounted for approximately 70% of the total pig cost in Spain
over the period from 2010 to 2014, while the significant fluctuation of feed prices further
increases economic risk [
2
]. The pork industry, especially in EU countries, is facing lower
profit margins per animal, leading to the need for new nutritional strategies to increase
its competitiveness and the farmers’ revenue [
2
,
3
]. Concurrently, food wastage within the
food production and consumption value chain remains a major global problem [
4
]; it is
estimated that approximately one third of food produced for human consumption is either
lost or wasted, amounting to a financial loss of about US$1 trillion per year [
5
]. In order to
reduce food losses and minimize animal production costs, researchers have been focused
on the evaluation of new sources of feed ingredients, such as agro-industrial by-products,
former food products (FFPs), etc., as alternatives to conventional feed ingredients. A
key advantage of these alternative feed ingredients is the reduced dependence in animal
production on cereals, which are also consumed by humans [6].
Among the alternative feed ingredients that can be used in animal ration formulations,
bakery FFPs and by-products can be an excellent choice due to their energy content; high
palatability; low levels of anti-nutritional agents, such as fiber, tannins, glucosinolates and
Sustainability 2023,15, 12827. https://doi.org/10.3390/su151712827 https://www.mdpi.com/journal/sustainability

Sustainability 2023,15, 12827 2 of 12
heat-labile trypsin inhibitors; and their constant availability on the market [
7
,
8
]. Dried
bakery meal (BM) is a mixture of breads, cookies, cakes, crackers, doughs, chips, pasta,
snacks, nuts, cereals, flour, baked goods and related food by-products that have been
separated from non-edible materials, mixed, ground and heat-treated [
9
,
10
]. These FFPs
are economical feed ingredients consisting of processed and ready-to-eat bakery products
that are no longer suitable for human consumption due to manufacturing or packaging
defects [
10
]. The use of FFPs in animal feed production is regulated by feed legislation, in
which there is a clear distinction between former food and food waste, that enables their
marketing as a safe feedstuff that cannot be degraded to food waste [11].
Feeding FFPs to livestock enables losses of high-quality food materials to be reduced,
returned to the supply chain and re-used [
12
,
13
]. Moreover, this practice aligns with the
concept and principles of circular economy, which implies the reduction of food waste
generated in the food systems, re-use of food by-products, nutrient recycling and a shift
in nutrition towards more diverse and more efficient food patterns [
14
]. In the European
Union, the use of FFPs has already been implemented in animal feed production. How-
ever, it remains limited (3.5 million tons/year) [
15
] compared to the total discarded food
(88 million tons/year) [16].
The inclusion of BM derived from food by-products as a feed ingredient in animal diets
has been mainly investigated as an alternative poultry and swine nutritional management
practice [
17
–
20
]. It can be assumed that 1 ton of BM is equivalent to 850 kg of corn, 90 kg
of soybean meal (44% w.w
−1
protein content) and 60 kg of fat/oil [
9
]. The nutritional
evaluation of six different mixtures of bakery by-products used in pig rations showed that
their nutritional composition is comparable to that of cereals [
15
]. BM has protein and
amino acid contents similar to those of corn (10.8% crude protein, 0.27% lysine and 0.10%
tryptophan) but higher fat content (11%). It is also rich in starch, as wheat flour is the main
ingredient in most bakery products. The starch contained in BM is thermally processed,
increasing its digestibility and nutritional value, rendering BM ideal for feeding growing
pigs [8].
However, there is a scarcity of research evidence regarding the optimal inclusion rate
of BM in piglets’ post-weaning diets, as well as its impact on growth performance and
welfare. In fact, despite the obvious advantages concerning feed sustainability due to the
more efficient use of natural resources (i.e., land, water, energy etc.), it is reported that
the main limiting factor of the use of FFPs is the lack of information on their nutritional
properties and their safe use in animal diets [
13
]. Therefore, the purpose of this study is to
systematically assess the effect of different levels (15% and 20% w.w
−1
) of BM inclusion
on the growth performance welfare and behavior indicators in post-weaning piglets. The
experimental trial was conducted in a commercial pig farm, employing different batches of
BM produced from various locally collected bakery FFPs, to closely simulate the constraints
and conditions of real, commercial-scale use of BM.
2. Materials and Methods
2.1. Bakery Meal Production
BM was produced in three different production batches. The bakery FFPs for BM
production consisted of pasta, cookies, cereals, chocolates, pastry, breads, croissants, etc.
that were still edible but not meant for human consumption. The amount of each bakery
FFP in the production batch changed depending on the availability of the by-products;
chocolates were always less than 10% w.w
−1
in all production batches. The bakery FFPs
were collected and gathered at a BM producing plant in northern Greece, unpacked,
ground and thermally treated. The thermal treatment comprised at least 20 min of retention
time, at 133
◦
C and 3 bar. During the thermal treatment, the BM weight was reduced by
approx.
60% w.w−1
due to moisture removal. The produced BM was a crumbling/coarse
brown powder, which was put into 20-kg bags and stored in a dry and cool place under
ambient conditions. Two samples from each batch of BM production were collected for
physicochemical and microbiological analysis.

Sustainability 2023,15, 12827 3 of 12
2.2. Bakery Meal Characterization
The physicochemical analysis of the basic nutrients was performed according to Euro-
pean Commission (EC) Regulation No. 152/2009 [
21
] for the following parameters: dry
matter, crude protein, ash, crude fats and crude fiber. The carbohydrate content and the
gross energy were calculated based on the proximate analysis. The sugar content was
measured via an enzymatic method used for mono- and di-saccharides analysis in plant
and food products (Megazyme K-SUFRG 04/18 assay kit, Megazyme, Wiklow, Irland). The
starch content was also determined enzymatically, employing the Megazyme K_TSA_100A
assay kit. The concentrations of mono-, poly-unsaturated and saturated fatty acids were
determined according to the EC Regulation No. 2568/91 [
22
]. The extracted fatty acids,
via the Soxhlet extraction method (Soxtherm SOX412-MACRO, Gerhardt GmbH & Co.
KG, Königswinter, Germany), were analyzed via GC-FID (GC-2010 Plus, Shimadzu Co.,
Japan) employing a Supelco SP2560 column, after alkaline transesterification according
to Dedousi et al. [
23
]. The peroxide value (PV) of lipids was determined according to
the EU 2568/91 method [
22
] based on the free iodine titration after oxidation of a potas-
sium iodide solution. The concentrations of aflatoxins B1, B2, G1 and G2 and mycotoxins
Deoxynivalenol (DON) and Zearalenone (ZON) were analyzed according to available pro-
tocols [
24
,
25
]. The BM was also microbiologically characterized via real-time PCR methods
for the following parameters: Enterobacteriaceae [
26
], Salmonella spp. [
27
], Campylobacter
spp. [
28
] and African swine fever virus (ASFV). More specifically, the presence of ASFV was
determined by using the commercial real-time PCR assay ID Gene African Swine fever Du-
plex (IDvet, Innovation Diagnostics Inc., Grabels, France). The kit includes an endogenous
positive control that is used for ensuring the correct DNA amplification. Additionally, the
method was validated for the detection of ASFV in the BM by spiking the ASFV positive
control in the crude sample. The results concerning the characterization of the BM are
summarized in Table 1.
Table 1.
Nutrient analysis, amino acid composition profile, aflatoxin and mycotoxin concentrations
and microbiological characterization of the BM used in this study. Data are presented as mean
values ±SD; the data comprise three production batches and six samples in total.
Parameter Amino Acids (g/kg)
Moisture and volatiles (g/100 g) 9.48 ±3.79 Alanine 11.5 ±8.4
Ash (g/100 g) 7.54 ±2.20 Arginine 9.4 ±5.7
Fat (g/100 g) 21.13 ±4.37 Aspartic acid 18.0 ±7.5
Proteins (g/100 g) 25.91 ±4.96 Glutaminic acid 31.0 ±19.1
Crude fibers % (g/100 g) 1.35 ±1.33 Glycine 25.2 ±11.4
Carbohydrates (g/100 g) 34.47 ±9.20 Histidine 9.6 ±9.4
Sugars (g/100 g) 5.79 ±6.33 Isoleucine 10.3 ±3.5
Starch (g/100 g) 19.33 ±2.95 Leucine 13.8 ±8.4
Energy (kcal/100 g) 431.7 ±35.7 Lysine 15.5 ±8.0
Fatty Acid (FA) Composition Methiononine 11.2 ±9.9
Monounsaturated FA—MUFA (% w.w−1)35.6 ±7.5 Phenyalanine 12.8 ±3.8
Polyunsaturated FA—PUFA (% w.w−1)14.2 ±3.8 Proline 23.5 ±24.7
Saturated FA—SFA (% w.w−1)50.2 ±13.7 Serine 11.9 ±4.9
Iodine value (meq O2/kg) <0.5 *–2.0 Threonine 10.1 ±4.5
Tryptophane 1.3 ±0.7
Tyrosine 8.3 ±3.7
Valine 12.3 ±4.9
Aflatoxins and Mycotoxins (µg/kg) Microbiological
characterization (cfu/g)
Aflatoxin B1 <0.5 *–4.5 Enterobacteriaceae <9.0 *–270
Aflatoxin B2 <0.5 *–1.0 Campylobacter spp. ND
Aflatoxin G1 <0.5 *–1.5 Salmonella spp. ND
Aflatoxin G1 <0.5 * ASFV 3ND
SUM of aflatoxins <2.0 *–7.0
ZON 1<2.0 *–31
DON 2<40 *–244
* This value is the detection limit of the assay. ND: not detected;
1
Zearalenone;
2
Deoxynivalenol;
3
African swine
fever Virus.

Sustainability 2023,15, 12827 4 of 12
2.3. Animals, Diets and Experimental Design
The experiment was conducted at the facilities of a commercial pig farm located
in Nea Tenedos, Chalkidiki, Greece (40
◦
21
0
48.3
00
N, 23
◦
15
0
49.7
00
E). Sixty post-weaning
castrated male piglets with intact tails (Pietrain breed, 28 days old, with mean body weight
8.57
±
0.20 kg) were selected for the study. The piglets were randomly allocated into
six consecutive pens (10 piglets.pen
−1
, space allowance 0.15 m
2
/piglet). Each pen had a
perforated plastic floor, was equipped with a feeder and nipple drinkers and was enriched
with iron chains serving as a toy for the piglets. The stocking density in each pen met the
requirements of EU directives [
29
]. All pens were at the same facility in order to obtain
the same environmental conditions for all groups. Piglets had ad libitum access to feed
and water. During the experimental period, the temperature and relative humidity were
automatically controlled and followed recommendations for the post-weaning production
phase [30].
After a seven-day adaptation period, the piglets were divided into 3 feeding treat-
ment groups: standard post-weaning diet with no BM added (CON), standard post-
weaning diet with 15% w.w
−1
BM added (BM 15) and standard post-weaning diet with
20% w.w
−1
BM added (BM 20), with 20 piglets.group
−1
, 2 replicates-pens.group
−1
and
10 piglets.replicate-pen−1
. A two-phase feeding program was applied for each dietary
treatment, consisting of a growing 1 diet, fed from 28 to 60 days of age, and a growing
2 diet, fed from 60 to 84 days of age. In total, 6 diets were formulated (Table 2). In the BM
diets, conventional ingredients, mainly corn and soya, were replaced with BM to formulate
all rations on an isonitrogenous and isocaloric basis. The rations were offered as mash and
met the National Research Council (NRC) energy requirements. The duration of the trial
was 56 days.
Table 2. Physical and chemical composition of experimental diets (dry matter basis).
Growing 1 (Days 28–60) Growing 2 (Days 60–84)
Items CON BM 15 BM 20 CON BM 15 BM 20
Ingredient composition
Maize meal 25.00 25.00 20.00 25.00 25.00 22.00
Corn 10.00 5.00 8.00 15.30 8.30 8.30
Wheat pollard 30.00 25.00 19.00 32.00 29.00 27.00
Bakery meal 0.00 15.00 20.00 0.00 15.00 20.00
Wheat 5.00 5.00 5.00 7.00 7.00 8.00
Soya 47 14.60 10.00 9.00 15.00 10.00 9.00
Vitamin and mineral premix 6.00 6.00 6.00 2.50 2.50 2.50
Soybean oil 2.00 1.60 0.60 0.00 0.00 0.00
Whey 5.00 5.00 10.00 0.00 0.00 0.00
NatuPro 2.00 2.00 2.00 2.00 2.00 2.00
Zinc Oxide 0.30 0.30 0.30 0.30 0.30 0.30
Mycotoxin binders 0.10 0.10 0.10 0.10 0.10 0.10
Marble powder 0.80 0.80 0.80
100.00 100.00 100.00 100.00 100.00 100.00
Chemical composition
Dry matter (%) 87.5 88.7 89.2 88.4 89.8 91.1
Crude protein (%) 15.26 14.42 14.43 14.25 13.62 13.27
Crude fiber (%) 3.59 3.28 3.23 3.21 2.95 2.71
Ether extract (%) 3.01 6.36 7.43 4.74 7.65 8.18
Crude ash (%) 3.24 3.35 3.46 2.69 2.84 3.32
Gross energy (Mj/kg) 15.57 16.04 16.22 13.98 14.59 14.14
Metabolizable energy (Mj/kg) 12.71 13.17 13.28 11.46 12.04 11.67
2.4. Production Traits
Body weight (BW) was measured individually at the beginning of the trial (28 day
of age) and then weekly, on a weighing platform (accuracy 0.5 kg) until the end of the

Sustainability 2023,15, 12827 5 of 12
experiment (84 days of age). Feed intake (FI) and mean average daily gain (ADG) per
pig were calculated at weekly intervals as well as for the whole experimental period
(
28–84 days
of age). Similarly, based on FI and ADG, the feed conversion ratio (FCR) per
pig was determined at weekly intervals and throughout the study. Orts were collected
and weighed once a week in order to calculate FI. Mortality rate was recorded daily. Body
condition score and health status were also evaluated on a weekly basis.
2.5. Welfare Assessment
Welfare and quality behavior indicators were assessed at the beginning of each eval-
uation day (10:00 a.m.) by the same evaluator. Welfare assessment was performed on a
weekly basis according to the suggested methodology of the Welfare Quality
®
Assessment
protocol for pigs [
31
]. The quality behavior characteristics (active, fearful, distressed, calm,
bored, playful, sociable, feeding) were interpreted by individual visual observations, with
a duration of 2 min in each pen. The number of piglets observed in each behavior category
was noted, divided by the total number of pigs in each group and multiplied by 100.
Moreover, piglets were individually scored for wounds on the body and incidences of
tail-biting during each 10 min observation period per pen. Wounds were inspected on both
sides of the body. Piglets were assigned a score of 0 when there was no evidence of wounds,
a score of 1 if all regions of the body had 5 to 10 lesions, and a score of 2 when >10 lesions
were observed on a minimum of 2 zones of the body or if any zone had >15 lesions. Tail-
biting incidence was evaluated using a 2-point scale; a score of 0 referred to no evidence of
tail-biting, while a score of 2 was indicative of bleeding tail and/or swollen infected tail
lesion and/or part of tail tissue missing and presence of crust [32].
2.6. Statistical Analysis
The data were tested for normality with the Shapiro–Wilk test before statistical analysis.
The piglet was considered the experimental unit. The significance of the differences
between welfare and quality behavior indicators among the groups was assessed via Chi-
square test. One-way analysis of variance (ANOVA) was used to compare means of the
examined parameters between different feeding treatments. Levene’s test was performed
to check homogeneity of variances. Post-hoc analysis was undertaken using the LSD test.
Significance level was set at p< 0.05. Data were analyzed using IBM SPSS v.22.0 (Armonk,
NY, USA: IBM Corp.).
3. Results
All animals remained clinically healthy throughout the study and no morbidity issues
were reported, with the exception of two piglets that died during the study, one from BM
15 group at the 4th week and one from CON group in the 6th week. Post mortem findings
were indicative of enzootic pneumonia. The available data of those animals were excluded
from the statistical analysis.
The BM supplementation in the piglets’ diet had a significant impact on ADG and
FCR during certain periods of the trial. Specifically, BM inclusion had a significant effect on
ADG from 57 to 63 and 78 to 84 days of age (p= 0.035 and p= 0.004, respectively). Moreover,
the experimental diets had a significant impact on FCR from 28 to 35 (p= 0.025), from 57 to
63 (p= 0.024) and from 78 to 84 (p= 0.003) days of age, respectively.
The effect of different levels of BM inclusion on growth and performance characteristics
among the three experimental groups are presented in Table 3. At 35 and 42 days of age,
BM-fed piglets presented higher BW compared to the CON group. However, significant
differences were observed only between the BM 15 and CON groups (p= 0.029 and 0.046,
respectively). Similarly, ADG was significantly higher in the BM 15 group from 28 to 35
(p= 0.039) and 78 to 84 (p= 0.003) days of age compared to the CON group. A significant
difference was reported between those groups during the fifth week of the trial, with ADG
being lower in the BM 15 group (p= 0.023). Additionally, higher ADG was observed in
the BM 20 group from 36 to 42 days of age (p= 0.033). Moreover, the BM 15 piglets had

Sustainability 2023,15, 12827 6 of 12
a higher FI from 36 to 42 and 50 to 56 days of life compared to the CON (p= 0.008) and
BM 20 (p= 0.004) ones, respectively. From 57 to 63 days, FI was lower in the BM 20 group
(p= 0.013)
. The best FCR was reported in the BM 15 group during the first and the last
week of the experimental period (p= 0.013 and 0.003, respectively). From 36 to 42 days,
FCR was lower in the BM 20 group compared to the CON group (p= 0.022). The BM 15
piglets had a higher FCR from 57 to 63 days of life compared to the CON and BM 20 groups
(p= 0.022 and 0.012, respectively). Overall, none of the evaluated performance parameters
differed significantly among the three groups (p> 0.05).
Table 3.
Growth and performance characteristics of piglets fed the control and diets containing
different levels of BM. Data are presented as mean ±SE values.
Variables CON BM 15 BM 20
BW (kg)
Day 28 8.66 ±0.22 8.74 ±0.12 8.32 ±0.20
Day 35 10.69 ±0.065 a11.32 ±0.15 b10.81 ±0.12 ab
Day 42 12.26 ±0.12 a13.42 ±0.18 b13.21 ±0.38 ab
Day 49 15.55 ±0.50 15.55 ±0.50 15.00 ±1.00
Day 56 19.50 ±0.50 21.06 ±0.06 20.50 ±0.50
Day 63 24.50 ±0.50 25.28 ±0.28 25.50 ±0.50
Day 70 31.06 ±0.06 31.06 ±0.06 31.00 ±0.01
Day 77 37.39 ±0.39 36.89 ±0.89 35.55 ±0.50
Day 84 43.72 ±0.72 45.84 ±0.84 44.50 ±0.50
Overall (28–84 d) 35.06 ±0.77 37.10 ±0.83 36.19 ±0.51
ADG (g)
28–35 d 289.64 ±1.78 a368.57 ±21.43 b355.71 ±17.14 ab
36–42 d 225.00 ±7.86 a300.71 ±5.00 ab 342.86 ±37.15 b
43–49 d 462.86 ±88.57 297.15 ±45.72 256.43 ±89.29
50–56 d 571.43 ±142.86 793.58 ±79.29 785.72 ±71.43
57–63 d 714.29 ±0.01 a602.86 ±31.43 b714.29 ±0.01 ab
64–70 d 936.43 ±79.29 825.72 ±31.43 785.72 ±71.43
71–77 d 904.29 ±47.15 832.86 ±188.57 642.86 ±71.43
78–84 d 905.00 ±47.86 a1278.57 ±7.14 b1285.71 ±0.01 b
Overall (28–84 d) 626.12 ±13.80 662.50 ±14.82 646.16 ±9.02
FI (Kg)
28–35 d 3.33 ±0.08 3.38 ±0.12 3.44 ±0.01
36–42 d 4.14 ±0.07 a4.67 ±0.08 b4.40 ±0.01 ab
43–49 d 6.40 ±0.02 6.36 ±0.06 6.49 ±0.08
50–56 d 7.32 ±0.04 ab 7.82 ±0.23 a6.78 ±0.28 b
57–63 d 8.96 ±0.04 b8.98 ±0.07 b8.55 ±0.05 a
64–70 d 9.28 ±0.28 9.06 ±0.06 8.88 ±0.08
71–77 d 14.78 ±0.28 14.60 ±0.16 14.40 ±0.15
78–84 d 14.89 ±0.29 15.09 ±0.24 14.50 ±0.10
Overall (28–84 d) 68.59 ±0.29 69.95 ±0.29 67.40 ±0.10
FCR
28–35 d 1.65 ±0.05 a1.31 ±0.03 b1.38 ±0.06 b
36–42 d 2.63 ±0.05 a2.22 ±0.08 ab 1.85 ±0.20 b
43–49 d 2.05 ±0.39 3.13 ±0.46 4.10 ±1.39
50–56 d 1.95 ±0.48 1.42 ±0.10 1.24 ±0.06
57–63 d 1.79 ±0.01 b2.14 ±0.01 a1.71 ±0.01 b
64–70 d 1.42 ±0.08 1.57 ±0.07 1.63 ±0.16
71–77 d 2.34 ±0.08 2.56 ±0.39 3.25 ±0.40
78–84 d 2.35 ±0.08 a1.69 ±0.04 b2.56 ±0.39 b
Overall (28–84 d) 1.96 ±0.04 1.89 ±0.04 1.86 ±0.03
a, b Mean values within a row with different superscripts differ significantly at p< 0.05.

Sustainability 2023,15, 12827 7 of 12
The percentages of piglets observed in the 3 dietary treatments (CON, BM 15, BM 20)
scoring for quality behavior characteristics (active, fearful, distressed, calm, bored, playful,
sociable, feeding) are presented in Table 4. On the majority of the evaluation days, the addition
of BM to the diets had no significant effect (p> 0.05) on quality behavior characteristics. At
day 63, BM 15 piglets were evaluated as more active compared to CON ones (p= 0.038).
Moreover, at day 70, BM 20 piglets were calmer compared to BM 15 and CON ones (p= 0.008
and 0.003, respectively).
Table 4.
Percentage (%) of piglets observed in the 3 dietary treatments (CON, BM 15, BM 20) scoring
for quality behavior characteristics (active, fearful, distressed, calm, bored, playful, sociable, feeding)
at each evaluation day.
Quality Behavior Characteristics
Active Fearful Distressed Calm Bored Playful Sociable Feeding
Day 35 CON 75.00 0 5 0 0 0 0 20.00
BM 15 80.00 0 0 0 0 0 0 20.00
BM 20 75.00 0 0 0 0 0 0 25.00
Day 42 CON 65.00 0 0 0 0 0 0 35.00
BM 15 70.00 0 0 0 0 0 0 30.00
BM 20 75.00 0 0 0 0 0 0 25.00
Day 49 CON 65.00 0 0 0 0 0 0 35.00
BM 15 60.00 0 0 0 0 0 0 40.00
BM 20 75.00 0 0 0 0 0 0 25.00
Day 56 CON 50.00 0 0 0 0 0 0 50.00
BM 15 52.63 0 0 0 0 21.05 0 26.32
BM 20 15.00 0 0 15.00 5.00 25.00 0 40.00
Day 63 CON 30.00 a0 0 5.00 5.00 5.00 5.00 50.00
BM 15 63.16 b0 0 0 0 5.26 0 31.58
BM 20 60.00 ab 0 0 0 0 15.00 0 25.00
Day 70 CON 26.32 0 0 31.58 b0 10.53 0 31.57
BM 15 42.10 0 0 26.32 b0 0 0 31.58
BM 20 15.00 0 0 85.00 a0000
Day 77 CON 42.10 0 0 10.53 0 10.53 0 36.84
BM 15 36.84 0 0 10.53 0 0 0 52.63
BM 20 40.00 0 0 20.00 0 10.00 0 30.00
a, b
Means within a column at a particular age for each type of behavior with different superscripts differ
significantly (p< 0.05).
Data regarding the impact of BM inclusion on body wounds and tail-biting incidence
are presented in Table 5. The percentage of piglets assigned a body wound score of 0, 1 or 2
did not differ significantly among different experimental groups (p> 0.005). However, a
significantly higher percentage of piglets with bleeding tails and/or swollen infected tail
lesions and/or missing parts of tail tissue and presence of crust was reported in the BM
15 group in the 3rd week and peaked in the 5th week of the trial (p< 0.005).

Sustainability 2023,15, 12827 8 of 12
Table 5.
Percentage (%) of piglets observed in the 3 dietary treatments (CON, BM 15, BM 20) scoring
for welfare indicators (body wounds, tail-biting incidence) on each evaluation day.
Welfare Indicators
Body Wounds 1Tail Biting Incidence 2
Score Score
01202
Day 35 CON 95.00 5.00 0 100 0
BM 15 95.00 0 0 100 0
BM 20 95.00 5.00 0 100 0
Day 42 CON 95.00 5.00 0 100 0
BM 15 90.00 10.00 0 100 0
BM 20 85.00 15.00 0 100 0
Day 49 CON 90.00 10.00 0 100 b0b
BM 15 95.00 5.00 0 80.00 a20.00 a
BM 20 80.00 20.00 0 100 b0b
Day 56 CON 85.00 10.00 5.00 100 b0b
BM 15 73.68 15.79 10.53 68.42 a31.58 a
BM 20 70.00 25.00 5.00 100 b0b
Day 63 CON 80.00 15.00 5.00 100 b0 b
BM 15 63.15 26.32 10.53 68.42 a31.58 a
BM 20 70.00 25.00 5.00 100 b0b
Day 70 CON 63.16 21.05 15.79 100 0
BM 15 42.11 21.05 36.84 89.48 10.52
BM 20 55.00 35.00 10.00 100 0
Day 77 CON 42.10 31.58 26.32 100 0
BM 15 26.31 26.32 47.37 89.48 10.52
BM 20 55.00 35.00 10.00 100 0
a, b
Means within a column at a particular age (Day 35–Day 77) for each score category 0–2 with different
superscripts differ significantly (p< 0.05).
1
Body Wounds: Score 0: no evidence of wounds; Score = 1: all regions
of the body had 5 to 10 lesions; Score = 2: >10 lesions were observed on a minimum of 2 zones of the body or any
zone had >15 lesions.
2
Tail biting: Score 0: no evidence of tail biting; Score = 2: bleeding tail and/or swollen
infected taillesion, and/or part of tail tissue missing and presence of crust.
4. Discussion
As asserted in the introduction, there is a notable scarcity of research data regarding
the inclusion of BM in the rations of post-weaned piglets. Digestibility and the effect of
bakery FFPs on growth performance have been mainly determined in growing–finishing
pigs [
33
–
36
], reporting conflicting results regarding feed efficacy. However, in most cases,
no depression in growth rate of the animals was observed.
Piglets are exposed to a variety of stressors during weaning, such as separation from
the dam, changes in housing environment, mixing with unfamiliar litters and transition
from milk to a solid diet [
37
]. The addition of BM to post-weaning diets could be a challenge
for their immature digestive systems. Nevertheless, BM can replace a significant percentage
of cereal grains in pig diets due to a chemical composition similar to that of wheat and
barley [
38
]. In our study, the chemical analysis of experimental BM diets revealed that
crude protein and metabolizable energy content were similar to conventional diets and
comparable with other studies [
1
,
39
]. The main concern in using BM in pig rations is the
variability in chemical and nutritional composition of each batch, according to the available
raw materials. However, it has been demonstrated that the nutrient profile of BM is rather
consistent regardless of the origin of production [40].
The inclusion of BM in post-weaning diets did not compromise the overall growth
performance of the piglets in our trial. At weekly intervals, significant differences in BW,
ADG and FCR were recorded among experimental groups. Although FI was lower in

Sustainability 2023,15, 12827 9 of 12
the CON group during the first weeks of the trial, overall performance and FCR were
not affected as the experiment progressed. Overall, although BW and ADG values were
numerically higher and FCR was better in the BM 15 and BM 20 groups, the differences
were not statistically significant. Those results are in accordance with what Tiwari et al. [
41
]
observed when they replaced maize in basal diets with different levels of bakery FFPs.
The inclusion of 20% w.w
−1
bakery FFPs resulted in the highest total weight gain and
ADG compared to 0%, 10% or 30% w.w
−1
levels, although the overall differences in
growth performance at the end of the trial were not statistically significant. Similarly,
Tretola et al. [
42
] did not report any depression in growth rate by using bakery, pasta and
confectionary by-products at levels up to 30% w.w
−1
in post-weaning diets. No detrimental
effects on growth and FCR were observed, even with high substitution of corn (50%)
with bakery FFPs [
43
]. On the contrary, Luciano et al. [
44
] recorded a decrease in overall
and ADG of pigs from day 15 to 35 as the concentration of BM increased in the diets,
indicating that a total replacement of maize may not be beneficial during this crucial period.
Narayanan et al. [
45
] performed a trial in 7-day-old piglets, in which the control group
were fed swine starter feed and the experimental group were fed crumbled biscuits, ad
libitum in both cases. The final body weights at the end of 8th week were 14.10
±
2.27 kg
and 10.97 ±1.6 kg for the control and the experimental group, respectively. Thus, protein
supplementation is necessary to obtain optimal growth when BM is provided as the only
feed source.
The inclusion of BM has been more extensively studied compared to trials conducted
in post-weaning piglets. In many of these studies, no significant differences in growth
performance parameters were observed between control and experimental groups. These
investigations have yielded valuable data on the optimal percentage of BM inclusion,
providing insights into its potential as a sustainable dietary component. Indicatively,
Manu et al. [
46
] concluded that discarded biscuits can make up to 30% of the ration of
growing pigs, replacing corn at about 60% adversely affecting carcass yield and quality.
Similarly, Barman et al. [
43
] and Tiwari and Dhakal [
8
] reported that bakery waste has
no detrimental effect on growth characteristics when it replaces corn at 50% or 75%, re-
spectively. These findings indicate the feasibility of using BM as a partial substitute for
conventional ingredients in growing pig diets without compromising growth performance.
However, it is important to consider the potential impact of higher levels of BM inclusion.
Ojediran et al. [
47
] reported that replacing corn with biscuit dough at a level of 37.5% had a
significant effect on the FCR of growing pigs. Similarly, Kumar et al. [
36
] indicated that the
percentage of bread waste inclusion in diets should not exceed the level of 50% in order
to eliminate the possibilities of FI decrease and gastrointestinal disorders. In light of the
available literature and the goal of maintaining optimal animal performance, we chose to
use the lowest inclusion rates of BM in our trial. This cautious approach aimed to minimize
the risk of potential negative effects on the post-weaning piglets’ growth and well-being.
To further optimize the use of BM in post-weaning diets, additional research is warranted.
Welfare and performance of livestock are strongly correlated with gut health [
48
].
Tretola et al. [
42
] reported that the composition of gut microbiota changed after the inclusion
of FFPs in the diets of post-weaning piglets. However, they did not measure the possible
effect of this addition on welfare indicators. To our knowledge, the present study is the first
one reporting the possible impact of BM incorporation in post-weaning diets on welfare and
quality behavior indicators. No evidence of severe welfare issues was reported during the
trial, with the exception of the tail-biting incidence in BM 15 group that was first reported
at day 49 and lasted approximately three weeks. There are a variety of risk factors that can
trigger this abnormal behavior, such as health issues, stress, feed, barn climate, stocking
intensity and lack of enrichment materials [
49
]. In our case, it was a challenge to identify the
cause of this outbreak, as preventative measures were applied in all groups. This behavior
affected performance characteristics of the group, mainly FCR and ADG parameters, during
the fifth week of the experiment. After the identification and separation of the biter, the

Sustainability 2023,15, 12827 10 of 12
remaining piglets recovered quickly, and their weight gain was compensated for during
the remaining weeks of the trial.
5. Conclusions
The results obtained in the present study provide valuable insights into the potential
utilization of BM in the formulation of post-weaning piglet diets. The inclusion of BM at
either 15% or 20% w.w
−1
caused no detrimental effects on the overall growth parameters
of the piglets. This finding is promising as it suggests that BM can be a sustainable and
cost-effective alternative in piglet nutrition without compromising their growth perfor-
mance. Moreover, the use of BM did not negatively impact the welfare and quality behavior
indicators for post-weaned piglets. Despite the reported variability in specific physico-
chemical characteristics of the different BM batches, it is noteworthy that this variability did
not seem to affect the reported results, and the use of the BM was successfully employed.
This resilience in the face of batch variation highlights the feasibility and adaptability of
incorporating BM into piglet diets, making it a reliable option for sustainable and circular
food practices. While this study sheds light on the growth and welfare aspects of using BM
in post-weaning piglet diets, there are still several unexplored areas that warrant further
investigation. Future research should delve into assessing the impact of BM inclusion
on other critical parameters, such as the gut microbiota composition, the carcass quality
through meat analysis and taste panel assessment and the overall pig farm environmental
and economic sustainability comprising a cost-benefit analysis. Understanding the effects
of BM on these aspects will provide a more comprehensive evaluation of its potential
benefits and implications for the pig farming industry.
Author Contributions:
Conceptualization, S.-A.T. and E.N.S.; methodology, A.D. and S.I.P.; software,
S.-A.T. and A.D.; validation, A.D., G.F.B. and E.N.S.; formal analysis, S.-A.T.; investigation, A.D.
and M.-Z.K.; resources, E.N.S.; data curation, S.-A.T. and E.N.S.; writing—original draft preparation,
S.-A.T.; writing—review and editing, A.D., M.-Z.K., G.F.B., S.I.P. and E.N.S.; visualization, G.F.B.
and S.I.P.; supervision, E.N.S.; project administration, E.N.S.; funding acquisition, S.I.P. and E.N.S. All
authors have read and agreed to the published version of the manuscript.
Funding:
This research has been co-financed by the European Regional Development Fund of the
European Union and Greek national funds through the Operational Program Competitiveness,
Entrepreneurship and Innovation, under the call RESEARCH–CREATE–INNOVATE (project code:
T2EDK-04537).
Institutional Review Board Statement:
The study was conducted in accordance with the Declaration
of Helsinki and approved by the Committee for Research Ethics of Hellenic Agricultural Organization
DIMITRA (Protocol Number 14948/6-03-2023).
Data Availability Statement:
The data presented in this study are available on request from the
corresponding author. The data are not publicly available due to privacy.
Acknowledgments:
We sincerely thank the pig farm CHALKIDIKI S.A, which provided the experi-
mental animals and facilities for this study, as well as Nektaria Papadaki for providing primary data.
Conflicts of Interest: The authors declare no conflict of interest.
References
1.
Luciano, A.; Tretola, M.; Ottoboni, M.; Baldi, A.; Cattaneo, D.; Pinotti, L. Potentials and Challenges of Former Food Products
(Food Leftover) as Alternative Feed Ingredients. Animals 2020,10, 125. [CrossRef] [PubMed]
2.
Rocadembosch, J.; Amador, J.; Bernaus, J.; Font, J.; Fraile, L.J. Production parameters and pig production cost: Temporal evolution
2010–2014. Porc. Health Manag. 2016,2, 11. [CrossRef] [PubMed]
3.
Hoste, R. International Comparison of Pig Production Costs 2018: Results of InterPIG; Wageningen Economic Research Report No.
2020-007; Wageningen University: Wageningen, The Netherlands, 2020. [CrossRef]
4.
Luciano, A.; Tretola, M.; Mazzoleni, S.; Rovere, N.; Fumagalli, F.; Ferrari, L.; Comi, M.; Ottoboni, M.; Pinotti, L. Sweet vs. Salty
Former Food Products in Post-Weaning Piglets: Effects on Growth, Apparent Total Tract Digestibility and Blood Metabolites.
Animals 2021,11, 3315. [CrossRef] [PubMed]
5. UN World Food Programme. Available online: https://www.wfp.org/foodwaste (accessed on 11 February 2023).

Sustainability 2023,15, 12827 11 of 12
6.
Zangeneh, S.; Torki, M. Effects of B-Mannanase Supplementing of Olive Pulp-Included Diet on Performance of Laying Hens, Egg
Quality Characteristics, Humoral and Cellular Immune Response and Blood Parameters. Glob. Vet. 2011,7, 391–398.
7.
Ramu, P. Performance and Nutrient Digestibility in Sheep Fed Diets Containing Varying Levels of Biscuit Waste. Ph.D. Thesis,
P.V. Narsimha Rao Telangana Veterinary University, Telangana, India, 2018.
8.
Tiwari, M.R.; Dhakal, H.R. Bakery Waste is an Alternative of Maize to Reduce the Cost of Pork Production. Int. J. Res. Agric. For.
2020,7, 1–9.
9.
Formulating Poultry and Pig Diets with Bakery Meal. News and Analysis on the Global Poultry and Animal Feed Industries.
Available online: https://www.wattagnet.com/home/article/15508699/formulating-poultry-and-pig-diets-with-bakery-meal
(accessed on 8 January 2023).
10.
Ottoboni, M.; Tretola, M.; Luciano, A.; Giuberti, G.; Galloc, A.; Pinotti, L. Carbohydrate digestion and predicted glycemic index of
bakery/confectionary ex-food intended for pig nutrition. Ital. J. Anim. Sci. 2019,18, 838–849. [CrossRef]
11.
EUR-Lex. Commission Notice of 16 April 2018 Laying down Guidelines for the Feed Use of Food No Longer Intended for Human
Consumption; Official Journal of the European Union: Brussels, Belgum, 2018; pp. 1–33. Available online: https://eur-lex.europa.
eu/legal-content/EN/TXT/?uri=CELEX%3A52018XC0416%2801%29 (accessed on 12 December 2022).
12.
Fausto-Castro, L.; Rivas-García, P.; Gomez-Nafte, J.A.; Rico-Martínez, R.; Rico-Ramírez, V.; Gomez-Gonzalez, R.; Cuaron-
Ibargüengoytia, J.A.; Botello-Alvarez, J.E. Selection of food waste with low moisture and high protein content from Mexican
restaurants as a supplement to swine feed. J. Clean. Prod. 2020,256, 120137. [CrossRef]
13.
Pinotti, L.; Luciano, A.; Ottoboni, M.; Manoni, M.; Ferrari, L.; Marchis, D.; Tretola, M. Recycling food leftovers in feed as
opportunity to increase the sustainability of livestock production. J. Clean. Prod. 2021,294, 126290. [CrossRef]
14.
Jurgilevich, A.; Birge, T.; Kentala-Lehtonen, J.; Korhonen-Kurki, K.; Pietikäinen, J.; Saikku, L.; Schösler, H. Transition towards
Circular Economy in the Food System. Sustainability 2016,8, 69. [CrossRef]
15.
Giromini, C.; Ottoboni, M.; Tretola, M.; Marchis, D.; Gottardo, D.; Caprarulo, V.; Baldi, A.; Pinotti, L. Nutritional evaluation of
former food products (ex-food) intended for pig nutrition. Food Addit. Contam. Part A Chem. Anal. Control. Expo. Risk Assess.
2017
,
34, 1436–1445. [CrossRef]
16.
Stenmarck, Å.; Jensen, C.; Quested, T.; Moates, G. Estimates of European Food Waste Levels. In Report of the Project FUSIONS
(Contract Number: 311972) Granted by the European Commission (FP7); IVL Swedish Environmental Research Institute: Stockholm,
Sweden, 2016; Available online: http://eu-fusions.org/phocadownload/Publications/Estimates%20of%20European%20food%
20waste%20levels.pdf (accessed on 15 January 2023).
17.
Mackenzie, S.; Leinonen, I.; Ferguson, N.; Kyriazakis, I. Can the environmental impact of pig systems be reduced by utilising
co-products as feed? J. Clean. Prod. 2016,115, 172–181. [CrossRef]
18.
Stefanello, C.; Vieira, S.L.; Xue, P.; Ajuwon, K.M.; Adeola, O. Age-related energy values of bakery meal for broiler chickens
determined using the regression method. Poult. Sci. J. 2016,95, 1582–1590. [CrossRef] [PubMed]
19.
Zhang, F.; Adeola, O. Energy values of canola meal, cottonseed meal, bakery meal, and peanut flour meal for broiler chickens
determined using the regression method. Poult. Sci. J. 2017,96, 397–404. [CrossRef] [PubMed]
20.
Babatunde, O.O.; Park, C.S.; Adeola, O. Nutritional Potentials of Atypical Feed Ingredients for Broiler Chickens and Pigs. Animals
2021,11, 1196. [CrossRef] [PubMed]
21.
EUR-Lex. Document 32009R0152, Commission Regulation (EC) No 152/2009 of 27 January 2009 Laying down the Methods of
Sampling and Analysis for the Official Control of Feed. Available online: https://eur-lex.europa.eu/legal-content/EN/ALL/
?uri=CELEX:32009R0152 (accessed on 8 March 2023).
22. EUR-Lex. Document 31991R2568, Commission Regulation (EEC) No 2568/91 of 11 July 1991 on the Characteristics of Olive Oil
and Olive-Residue Oil and on the Relevant Methods of Analysis. Available online: https://eur-lex.europa.eu/legal-content/en/
ALL/?uri=CELEX:31991R2568 (accessed on 8 March 2023).
23.
Dedousi, A.; Kritsa, M.-Z.; Ðuki´c Stojˇci´c, M.; Sfetsas, T.; Sentas, A.; Sossidou, E. Production Performance, Egg Quality Character-
istics, Fatty Acid Profile and Health Lipid Indices of Produced Eggs, Blood Biochemical Parameters and Welfare Indicators of
Laying Hens Fed Dried Olive Pulp. Sustainability 2022,14, 3157. [CrossRef]
24.
Vendl, O.; Berthiller, F.; Crews, C.; Krska, R. Simultaneous determination of deoxynivalenol, zearalenone, and their major masked
metabolites in cereal-based food by LC-MS-MS. Anal. Bioanal. Chem. 2009,395, 1347–1354. [CrossRef]
25.
Ouakhssase, A.; Chahid, A.; Choubbane, H.; Aitmazirt, A.; Addi, E.A. Optimization and validation of a liquid chromatogra-
phy/tandem mass spectrometry (LC-MS/MS) method for the determination of aflatoxins in maize. Heliyon
2019
,5, e01565.
[CrossRef]
26.
ISO Standard No. 21528-2; Microbiology of the Food Chain—Horizontal Method for the Detection and Enumeration of
Enterobacteriaceae—Part 2: Colony-Count Technique. International Organization for Standardization: Geneva, Switzerland,
2017.
27.
ISO Standard No. 6579-1; Microbiology of the Food Chain—Horizontal Method for the Detection and Enumeration of Salmonella—
Part 1: Detection of Salmonella spp. International Organization for Standardization: Geneva, Switzerland, 2017.
28.
ISO Standard No. 10272-2; Microbiology of the Food Chain—Horizontal Method for the Detection and Enumeration of Campy-
lobacter spp.—Part 2: Colony-Count Technique. International Organization for Standardization: Geneva, Switzerland, 2017.

Sustainability 2023,15, 12827 12 of 12
29.
EUR-Lex. Council Directive 2008/120/EC of 18 December 2008 Laying down Minimum Standards for the Welfare Qual-
ity
®
Assessment Protocol for Pigs (Sows and Piglets, Growing and Finishing Pigs). Available online: https://food.ec.europa.eu/
system/files/2016-12/aw_practice_farm_pigs_stfwrkdoc_en.pdf (accessed on 8 March 2023).
30.
Fernandez, M.D.; Losada, E.; Ortega, J.A.; Arango, T.; Ginzo-Villamayor, M.J.; Besteiro, R.; Lamosa, S.; Barrasa, M.; Rodriguez,
M.R. Energy, Production and Environmental Characteristics of a Conventional Weaned Piglet Farm in North West Spain. Agronomy
2020,10, 902. [CrossRef]
31.
Welfare Quality. Assessment Protocol for Pigs (Sows and Piglets, Growing and Finishing Pigs); Welfare Quality Consortium: Lelystad,
The Netherlands, 2009; Available online: http://www.welfarequalitynetwork.net/media/1018/pig_protocol.pdf (accessed on 20
November 2022).
32.
Alpigiani, I. Associations between Animal-Based Welfare Measures and the Presence of Yersinia Enterocolitica and Salmonella spp.
as Indicators of Food Safety in Finishing Pigs at Slaughter Plants in Northern Italy. Ph.D. Thesis, University of Parma, Parma,
Italy, 2013.
33.
Almeida, F.N.; Petersen, G.I.; Stein, H.H. Digestibility of amino acids in corn, corn coproducts, and bakery meal fed to growing
pigs. J. Anim. Sci. 2011,89, 4109–4115. [CrossRef]
34.
Paulk, C.B.; Nitikanchana, S.; Prusa, K.J.; Tokach, M.D.; Goodband, R.D.; DeRouchey, J.M.; Nelssen, J.L.; Dritz, S.S. Effects of
increasing dietary bakery by-product on growing-finishing pig growth performance and carcass quality. Kans. Agric. Exp. Stn.
Res. Rep. 2012,10, 155–165. [CrossRef]
35.
Rojas, J.; Liu, Y.; Stein, H.H. Phosphorus digestibility and concentration of digestible and metabolizable energy in corn, corn
coproducts, and bakery meal fed to growing pigs. J. Anim. Sci. 2013,91, 5326–5335. [CrossRef]
36.
Kumar, A.; Roy, B.; Sirohi, R.; Singh, Y.; Singh, D.N. Effect of Bread Waste Feeding on Growth Performance and Carcass Traits of
Crossbred Pigs. J. Anim. Res. 2016,6, 117–120. [CrossRef]
37.
Hötzel, M.J.; de Souza, J.P.P.; Dalla Costa, O.A.; Machado Filho, L.C.P. Disentangling the effects of weaning stressors on piglets’
behaviour and feed intake: Changing the housing and social environment. Appl. Anim. Behav. Sci. 2011,135, 44–50. [CrossRef]
38. Pinotti, L.; Ottoboni, M.; Luciano, A.; Savoini, G.; Cattaneo, D.; Tretola, M. Ex-Food in Animal Nutrition: Potentials and Challenges;
Chizzotti, M.L., Ed.; Energy and Protein Metabolism and Nutrition, EAAP Publication n. 138; Wageningen Academic Publishers:
Wageningen, The Netherlands, 2019; pp. 47–52.
39.
Guo, J.Y.; Phillips, C.E.; Coffey, M.T.; Kim, S.W. Efficacy of a supplemental candy coproduct as an alternative carbohydrate source
to lactose on growth performance of newly weaned pigs in a commercial farm condition. J. Anim. Sci.
2015
,93, 5304–5312.
[CrossRef] [PubMed]
40.
Liu, Y.; Jha, R.; Stein, H.H. Nutritional composition, gross energy concentration, and
in vitro
digestibility of dry matter in 46
sources of bakery meals. J. Anim. Sci. 2018,96, 4685–4692. [CrossRef] [PubMed]
41.
Tiwari, M.R.; Dhakal, H.R.; Sah Sudi, M. Growth comparison of piglets fed with different level of bakery waste in basal diet. J.
Agric. For. 2020,4, 261–267. [CrossRef]
42.
Tretola, M.; Ottoboni, M.; Luciano, A.; Rossi, L.; Baldi, A.; Pinotti, L. Former food products have no detrimental effects on diet
digestibility, growth performance and selected plasma variables in post-weaning piglets. Ital. J. Anim. Sci.
2019
,18, 987–996.
[CrossRef]
43.
Barman, K.; Tamuli, M.K.; Sarma, D.K.; Banik, S.; Mohan, N.H.; Thomas, R.; Gokuldas, P.P.; Pegu, S.R.; Kaushik, P. Effect of
Replacing Maize with Bakery Waste on the Performance of Growing Crossbred Pigs. Anim. Nutr. Feed Technol.
2016
,16, 165–170.
[CrossRef]
44.
Luciano, A.; Espinosa, C.D.; Pinotti, L.; Stein, H.H. Standardized total tract digestibility of phosphorus in bakery meal fed to pigs
and effects of bakery meal on growth performance of weanling pigs. Anim. Feed Sci. Technol. 2022,284, 115148. [CrossRef]
45.
Narayanan, R.; Ronald, B.S.M.; Baegan, S.; Bharathidasan, A. Biscuit powder as an unconventional feed in piglet. Indian J. Anim.
Res. 2009,43, 215–216.
46.
Manu, F.; Okai, D.B.; Boateng, M.; Frimpong, Y.O. Nutrient composition, pest and microbial status and effects of discarded
biscuits on the growth performance, carcass characteristics and economic profiles of growing-finishing pigs. Afr. J. Food Agric.
Nutr. Dev. 2015,15, 1684–5374. [CrossRef]
47.
Ojediran, T.; Bamigboye, D.; Olonade, G.; Ajayi, A.; Emiola, I. Growth response, cost benefit, carcass characteristics and
organoleptic properties of pigs fed biscuit dough as a replacement for maize. Acta Fytotech. Zootech. 2019,22, 58–63. [CrossRef]
48.
Chan, C.; Luo, S.; Yan, C. Gut Microbiota Implications for Health and Welfare in Farm Animals: A Review. Animals
2022
,12, 93.
[CrossRef] [PubMed]
49.
Kakanis, M.; Marinou, K.; Sossidou, E. Greek Pig Farmers’ Perceptions and Experiences of Tail Biting and Tail Docking. Animals
2023,13, 672. [CrossRef]
Disclaimer/Publisher’s Note:
The statements, opinions and data contained in all publications are solely those of the individual
author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to
people or property resulting from any ideas, methods, instructions or products referred to in the content.