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ABSTRACT: 1. The influence of pellet diameter and length on the quality of pellets and performance, nutrient utilisation and digestive tract development of broilers given wheat-based diets was examined from 10 to 42 d of age. The experimental design was a 2 × 2 factorial arrangement of treatments evaluating two pellet diameters (3 and 4.76 mm) and two pellet lengths (3 and 6 mm). From 0 to 9 d of age, all birds were offered a common starter diet pelleted with a 3-mm diameter die and 3-mm length. Broiler grower (d 10 to 21) and finisher (d 22 to 42) diets, based on wheat, were formulated and then subjected to the 4 different treatments. 2. In grower diets, increasing pellet diameter and pellet length reduced the gelatinised starch (GS) content of the diets. In finisher diets, GS content of 3-mm diameter pellets did not change with increasing pellet length but decreased in 4.76-mm diameter pellets. 3. In grower and finisher diets, increments in intact pellet weight, pellet durability index and pellet hardness with increasing pellet length were greater in 3-mm diameter pellets than those with 4.76-mm diameter. 4. Increasing pellet length from 3 to 6 mm increased apparent metabolisable energy values. Neither the interaction nor main effects were significant for the ileal digestibility of nitrogen and starch. 5. During the grower period (d 10 to 21), birds given pellets of 6-mm length had greater body-weight gain than those given 3-mm length pellets. Feeding 6-mm length pellets decreased feed per body-weight gain compared to 3-mm length pellets. During the finisher (d 22 to 42) and whole grow-out (d 10 to 42) periods, while different pellet lengths had no effect on feed per body-weight gain values at 3-mm pellet diameter, increasing the pellet length decreased feed per body-weight gain at 4.76-mm pellet diameter. 6. Increasing pellet diameter and pellet length reduced the relative length of duodenum. Birds given 3-mm diameter pellets had heavier proventriculus compared to those given 4.76-mm diameter pellets. 7. Overall, the data suggest that increasing the pellet length from 3 to 6 mm improved the body-weight gain and feed per body-weight gain during the grower period (d 10 to 21). While the positive effect on body-weight gain disappeared as the birds grew older, improvements in feed per body-weight gain were maintained over the finisher and whole grow-out periods only in 4.76-mm diameter pellets. Small diameter die holes and longer pellet lengths may be considered as potential manipulations to manufacture high-quality pellets under low conditioning temperatures.
British Poultry Science 05/2013; · 1.00 Impact Factor
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ABSTRACT: The addition of microbial phytase to diets for broiler chickens has been shown to improve the availability of phytate P, total P, some other minerals, and amino acids. In this study, the effect of a novel microbial phytase expressed by synthetic genes in Aspergillus oryzae on amino acid and mineral availability was assessed. Phytase was incorporated (1,000 and 2,000 U/kg) into low-P corn-soybean meal-based diets for broilers. Broilers received the experimental diets for 3 wk, and excreta were collected from d 18 to 21 for the determination of AME and mineral retention. On the 22nd day, the broilers were killed and the left leg removed and ileal digesta collected. Ileal phytate P and total P absorption, ileal amino acid digestibility, as well as the bone mineral content and bone mineral density were determined. Ileal phytate P absorption and absorbed phytate P content of the low-P corn-soybean meal diet were significantly (P < 0.05) higher after dietary inclusion of the novel phytase (49-60% and 65-77% higher, respectively). Apparent ileal total P absorption and apparent total P retention was 12 to 16% and 14 to 19% higher (P < 0.05), respectively, after dietary inclusion of phytase. The bone mineral content and bone mineral density in the tibia were 32 to 35% and 19 to 21% higher (P < 0.05), respectively, after dietary phytase inclusion. The apparent ileal digestibility of threonine, tyrosine, and histidine increased significantly (P < 0.05) by 14, 9, and 7%, respectively, after dietary inclusion of microbial phytase. Overall, the inclusion of a novel microbial phytase into a low-P corn-soybean meal diet for broiler chickens greatly increased phytate P and total P absorption, bone mineral content and density, as well as the digestibility of some amino acids.
Poultry Science 05/2012; 91(5):1118-27. · 1.73 Impact Factor
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ABSTRACT: 1. The influence of conditioning temperature on the performance, nutrient utilisation and digestive tract development of broilers fed on maize- and wheat-based diets was examined up to 21 d of age. The experimental design was a 2 × 3 factorial arrangement of treatments evaluating two grain types (maize and wheat) and three conditioning temperatures (60°C, 75°C and 90°C). Broiler starter diets, each based on one grain (maize or wheat), were formulated and pelleted at the three temperatures. 2. Increasing conditioning temperature decreased the body-weight gain and feed intake in wheat-based diets, but birds fed on maize-based diets conditioned at 60°C and 90°C had higher body-weight gain and feed intake than those fed on the diet conditioned at 75°C. Increasing conditioning temperature increased feed per body-weight gain in both grain-type diets but improved pellet durability index (PDI) only in wheat-based diets; PDI was unaffected in maize-based diets. 3. In wheat-based diets, increasing conditioning temperature decreased the ileal digestibility of nitrogen and starch. Ileal nitrogen digestibility of maize-based diets conditioned at 60°C and 90°C was higher than at 75°C. Starch digestibility was unaffected by conditioning temperature in maize-based diets. No effect of conditioning temperature was found for apparent metabolisable energy (AME). Increasing conditioning temperature decreased digestible protein and AME intakes in wheat-based diets but, in maize-based diets, birds fed on the diet conditioned at 75°C had lower digestible protein and AME intakes compared to those fed on diets conditioned at 60°C and 90°C. 4. Small intestine was longer in birds fed on diets conditioned at 75°C and 90°C compared with those fed on diets conditioned at 60°C. 5. Overall, the data suggest that while the effects of conditioning temperature on body-weight gain and feed intake of broilers to 21 d of age differed depending on the grain type, feed per body-weight gain was adversely affected by higher conditioning temperatures.
British Poultry Science 10/2010; 51(5):648-57. · 1.00 Impact Factor
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ABSTRACT: The ingredients and the macro- and micro-nutrient contents of diets that are fed to captive kiwi at seven New Zealand holding facilities were subject to analysis. The nutrient compositions were compared across facilities and with an estimate of the nutrient composition of the diets of wild kiwi based on the intake of various dietary ingredients reported in the literature. A total of 20 ingredients were used, the number and proportion of these ingredients varied greatly between facilities. Six of the diets were based primarily on meat and three comprised a mixture of meat and cat biscuits. Just one included a proprietary insectivore mix. Nutrient content varied greatly between the seven diets, organic matter ranging from 91.8 to 95.6%, crude protein from 41.9 to 62.9%, and crude fat from 9.0 to 28.7% of dry matter content. Large variations were found in the total content and profile of amino acids and of fatty acids of the diets. The nutrient content of all seven diets differed from that of the natural diet of wild kiwi. Hence, the presence of nutrient deficiencies in the current formulations cannot be excluded
Zoo Biology 01/2010; 29:537-550. · 0.84 Impact Factor
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ABSTRACT: 1. Two experiments were conducted to measure changes in nutrient utilisation in the newly hatched broiler chicken. The first experiment determined the nitrogen-corrected apparent metabolisable energy (AME(N)) and total tract digestibility of starch and fat in diets based on wheat, sorghum and maize during the first two weeks post-hatch. The second experiment was conducted to confirm the results of Experiment 1 using wheat- and maize-based diets and was of 21 d duration. 2. In both experiments, changes to AME(N) with age were similar irrespective of the diet type, declining from d 3 to d 5-9 and then increasing after d 9. 3. In Experiment 1, the total tract digestibility of starch and fat exhibited a pattern similar to that of AME(N). 4. In Experiment 1, cereal effects were significant, with maize- and sorghum-based diets having higher AME(N) values than the wheat-based diet. Total tract starch digestibility determined for d 5, 7 and 14 showed no cereal differences. Total tract fat digestibility on d 7 was significantly lower for the wheat- and sorghum-based diets than for the maize-based diet, but no cereal differences were observed on d 5 or 14. 5. In Experiment 2, cereal effects were significant, with the maize-based diet having a higher AME(N) than the wheat-based diet. 6. These results showed that nutrient utilisation is compromised during the first week of life of the broiler chick.
British Poultry Science 08/2008; 49(4):429-35. · 1.00 Impact Factor
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ABSTRACT: To compare the effects of four stocking densities (5, 10, 15 or 20 birds per m2) on the performance, carcass characteristics and selected welfare indicators of broiler chickens.
A total of 756 day-old male broiler chicks were assigned as six replicates of 13, 25, 38 and 50 birds per pen, to stocking densities of 2,000, 1,000, 667 and 500 cm2 floor space per bird, respectively. The birds were housed in floor pens in an environmentally controlled room. Normal commercial diets were fed ad libitum and fresh water was freely available throughout the 5-week study period. Liveweights of birds and feed intake were recorded at weekly intervals. Data on carcass parameters and welfare indicators (moisture, gait scores, feather scores, breast and hip lesions, and foot pad and hock burns) were obtained on Day 35. Adrenal glands were removed at slaughter, weighed and examined histologically to determine the total proportion of cortical and medullary tissues.
During the study, the birds at the lowest density grew faster (p<0.001-0.01) and consumed more (p<0.001- 0.01) feed than those at the other three stocking densities. The liveweight gains and feed intake of birds reared at densities of 10, 15 and 20 birds per m2 were similar (p=0.11-0.83 and p=0.17-0.57, respectively). Stocking density had no influence on the feed/weight gain, mortality or carcass characteristics. No breast or hip lesions were observed in carcasses from any of the groups. The weight and structure of the adrenal glands were similar across all groups although the staining of medullary tissue of birds was most intense in the highest stocking density group. As stocking density increased, so did moisture and gait score, hock and foot pad burn scores, and the feather score was adversely affected.
The data showed that the relationship between stocking density and productivity traits was not linear in nature, in accordance with other studies. Under the conditions of the current study, the performance, mortality and carcass characteristics of broilers grown at densities of 10, 15 and 20 birds per m2 were similar. There were some welfare implications at high population densities as indicated by adverse effects on litter quality, gait scores and the incidence of hock and foot pad burns.
New Zealand veterinary journal 05/2004; 52(2):76-81. · 0.89 Impact Factor
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Asian-Australasian Journal of Animal Science 15 (2002) 10. - ISSN 1011-2367.
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ABSTRACT: The effect of storage on the nutritional quality of meat and bone meal was investigated. Three meat and bone meal samples were stored for 1, 2, 3, 6 and 9 months, with or without the addition of the antioxidants (butylatedhydroxytoluene and butylatedhydroxyanisole). Gross composition, thiobarbituric acid reactive substances (TBARS), gross amino acid content and the coefficient of the ileal apparent digestibility (CIAD) of amino acids was determined at each time point. The concentration of TBARS increased sharply during the first 2 months of storage thereafter TBARS decreased until 9 months. The addition of antioxidants to the meat and bone meal significantly decreased the TBARS compared to the unsupplemented samples. There was a significant (P<0.05) effect of time on the dry matter, crude protein, crude fat, cysteine, histidine and methionine content. There was no significant (P>0.05) effect of antioxidant addition or the interaction between time and antioxidant addition on the gross content of nutrients. A significant quadratic trend over time was obtained for the dry matter content while no significant linear or quadratic regression was obtained for the other components. There was no significant (P>0.05) effect of time, antioxidant addition or the interaction between time and antioxidant addition on the CIAD of any of the amino acids with the exception of methionine and cysteine for which a significant (P<0.05) effect of time was found. The CIAD of methionine decreased linearly over time while no significant trend was found for cysteine. Storage of meat and bone meal at ambient temperatures, although resulting in oxidation of the fat, does not add to the variation in the CIAD of amino acids normally observed
Animal Feed Science and Technology 127 (2006) 1-2.
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ABSTRACT: The influence of feeding with starter diets containing spray-dried bovine colostrum (SBC), spray-dried bovine plasma (SBP), or spray-dried porcine plasma (SPP) on the growth performance and gut morphology of broiler chickens was investigated. The crude protein, lysine, and methionine plus cystine contents (g/kg as received) of SBC, SBP, and SPP were determined to be 766, 736, and 684; 58, 61, and 55; and 27, 28, and 24, respectively. The 3 test proteins were incorporated into a maize-soybean meal diet at a level of 50 g/kg and fed to 6 replicates of 8 male broiler chicks from 1 to 14 days of age. On Day 14, the experimental diets were replaced with a common grower-finisher diet, which was offered until Day 35. Dietary treatments had no effect (P > 0.05) on the weight gain or feed intake of birds during the first 14 days. However, feed/gain of birds fed the SBC diet was lower (P < 0.05) than of those fed the control diet. A trend for a reduction in feed/gain (P = 0.06) was observed in SBP and SPP diets. Dietary treatments had no effect (P > 0.05) on performance during Days 14-35 or Days 1-35. Villus height was increased by 5.7% (P < 0.05) and 4.6% (P = 0.05) in birds fed the SPP and SBP diets, respectively, compared with those fed the control diet. Crypt depth was 6% greater (P < 0.05) in birds fed the SPP diet and tended (P = 0.08) to be greater in birds fed the SBC diet, compared with birds fed the control. The ratio of villus height to crypt depth tended (P = 0.06) to be lower in birds offered the SBC diet compared with the control. Crypt goblet cell density was reduced (P < 0.05) by 13.9% in birds fed the SBC diet, compared with control birds. These results suggest that feeding with diets containing the SBC, SBP, and SPP during 1-14 days of age has some beneficial effects on broiler chickens. Further studies are needed to evaluate these products in less sanitary environments, which may increase the positive responses.
King, M.R., Ravindran, V., Morel, P.C.H., Thomas, D.V., Birtles, M.J. and Pluske, J.R. <http://researchrepository.murdoch.edu.au/view/author/Pluske, John.html> (2005) Effects of spray-dried colostrum and plasmas on the performance and gut morphology of broiler chickens. Australian Journal of Agricultural Research, 56 (8). pp. 811-817.
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ABSTRACT: Two experiments were conducted to test the hypothesis that a lipase-based enzyme preparation would increase the AME content of full-fat rice bran (FFRB) by increasing fat digestibility when fed to broiler chickens. Experiment 1 used FFRB from Australia and lasted for 35 days, while Experiment 2 used FFRB from Thailand and lasted for 14 days. Rice bran was substituted in a maize-soybean diet at levels of 90 g/kg (Experiment 1) and at 90 and 180 g/kg in Experiment 2. Total collections of excreta were used for determination of AME content and fat digestibility. In Experiment 1, the enzyme increased the AME content of FFRB between days 4-7, 18-21 and 32-35 by 6.1-16.1% (p>0.05), however this was not associated with improved fat digestibility. In Experiment 2, the enzyme enhanced the AME content of FFRB between days 4-7 (10.42 vs. 9.06, p=0.107) and 11-14 (11.94 vs, 9.93, p=0.041), but again, this was not caused by increased fat digestibility. Inclusion of 180 g/kg depressed the AME content of FFRB by 7.4-11.5% (p>0.10) in conjunction with decreased (p<0.05) fat digestibility between 0-14 days of age. Improvements in bird growth with the enzyme were seen in Experiment 2 but not in Experiment 1. Increases in AME content of FFRB per se were not caused by enhanced fat digestibility, suggesting that the side activities associated with the preparation must have acted singularly or in combination to improve AME content and bird performance. These data show that the response of FFRB to the lipase-based enzyme preparation was dependent upon the geographical origin of the rice bran and the level of FFRB substituted in the basal diet.
Tan, S.H., Thomas, D.V., Camden, B.J., Kadim, I.T., Morel, P.C.H. and Pluske, J.R. <http://researchrepository.murdoch.edu.au/view/author/Pluske, John.html> (2000) Improving the Nutritive Value of Full-Fat Rice Bran for Broiler Chickens Using a Lipase-Based Enzyme Preparation. Asian-Australasian Journal of Animal Sciences, 13 (3). pp. 360-368.
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ABSTRACT: The apparent ileal amino acid digestibility in 15 meat and bone samples was compared in growing broiler chickens and growing laboratory rat. The animals were given a diet containing meat and bone meal as the sole source of protein. All diets contained chromic oxide as the indigestible marker to calculate the digestibility estimates. Comparison of digestibility data shows that, for all dispensable amino acids, apparent ileal amino acid digestibility was similar (p>0.05) between broiler chicken and the growing rat. However, the ileal amino acid digestibility was similar (p>0.05) between the two species for only four (histidine, methionine, threonine and valine) of the nine indispensable amino acids. Significant differences (p<0.01 to 0.05) were observed between the estimates in the broiler chicken and the rat for arginine, leucine, lysine, phenylalanine and cystine. Differences approaching statistical significance were observed for isoleucine (p=0.06) and tyrosine (p=0.10). For the amino acids, which differed between the species, the values obtained for broilers were consistently 4 to 7 percentage units lower than those in the rats. The exception was cystine, with digestibility in broilers being 17 percentage units lower than in the rat. The present data do not support the use of the growing rat as a model for growing chickens in the determination of ileal amino acid digestibility.
International Journal of Poultry Science. 4(4):192-196.
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ABSTRACT: Meat and bone meal is a valuable protein and mineral source in diets of production animals and contributes to the protein, energy and mineral component of diets. The aim of the present study was to more accurately characterise the apparent ileal amino acid digestibility of meat and bone meals produced in New Zealand and evaluate routine in vitro assays used in practise to measure meat and bone meal quality. A total of 94 commercial meat and bone meals from 25 New Zealand rendering plants over a two and a half year period were analysed for proximates, gross energy, gross amino acid content (incl. hydroxyproline, hydroxylysine and lanthionine), apparent ileal amino acid digestibility, pepsin nitrogen digestibility, protein solubility and bone content. The mean crude protein content of the 94 meat and bone meal samples was 56.8% with a range of >35% units and a coefficient of variation of 9.8%. The mean crude fat and ash content were 10.0 and 28.4% respectively. These latter components showed a large range (16 and 43%, respectively) with coefficients of variation above 22%. Amino acid digestibility between samples was highly variable with lysine and sulphur amino acids digestibility ranging between 45.8-89.0 and 38.2-85.5%, respectively. Pearson correlation coefficients are presented between crude protein content and individual gross amino acids, crude protein content and individual digestible amino acid content, and pepsin N digestibility and individual digestible amino acid content. There was a significant relationship between the digestible amino acid nitrogen content and the crude protein content while pepsin nitrogen digestibility was not correlated to ileal amino acid nitrogen digestibility (r=-0.06). Meat meals with a high protein content had relatively low hydroxyproline and hydroxylysine levels something that was attributed to the levels of collagen from bone. The data indicated that lanthionine (formed upon heat treatment of cysteine with a hydroprotein) is not a good indicator of the heat treatment employed to meat and bone meals. Step-wise multiple regression equations to predict the apparent digestible content of amino acids from rapid in vitro assays are presented. The most selected variables included ash and crude fat content. In general the equations derived for the essential amino acids had a higher degrees of fit (R-2) compared to the non-essential amino acids. The R-2 for the essential amino acids ranged from 0.43 for histidine and 0.68 for leucine. These equations provide a means of more rapidly estimating the apparent ileal digestible amino acid content (protein quality) of meat and bone meal using standard analyses.
Asian-Australasian Journal of Animal Sciences. 15(10):1507-1516.
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ABSTRACT: Variation in the apparent ileal digestibility of amino acids in 19 meat and bone meal samples, obtained from commercial rendering plants in New Zealand, was determined using 5-week-old broilers. Assay diets contained meat and bone meal as the only source of protein, and chromic oxide as an indigestible marker for the calculation of amino acid digestibility values. Correlations of chemical composition (crude protein, ash, crude fat, and gross energy) and in vitro assays (protein solubility in 0.2% potassium hydroxide and nitrogen digestibility by 0.2% pepsin hydrolysis) with ileal amino acid digestibility were also examined. Considerable variation was observed in the contents of crude protein (38.5-67.2 g/100 g), ash (13.0-56.5 g/100 g), crude fat (4.3-15.3 g/100 g), and gross energy (9.4-22.3 MJ/kg) of meat and bone meal samples. The amino acid concentrations and ileal digestibility of amino acids also varied substantially. Cystine, the first limiting amino acid in meat and bone meal, had the lowest digestibility estimates. Correlation analyses showed that the ash content was the only chemical parameter that was consistently correlated with amino acid digestibility. Digestibility of amino acids, with the exception of aspartic acid, threonine, serine, tyrosine, histidine, and cystine, was negatively correlated with ash content, with samples with high ash levels having lower digestibility. Both in vitro assay measurements were found to be insensitive indicators of variations in amino acid digestibility.
Australian Journal of Agricultural Research. 53(11):1257-1264.
