A.W. Jongbloed’s research while affiliated with Wageningen University & Research and other places

Techniques to determine N availability and fermentation characteristics of protein in the hindgut of pigs are not available. The gas production technique (Cone et al., 1996) determines fermentation characteristics of OM and can also be used after pre-digestion of the samples with pepsin and pancreatic enzymes to determine fermentation characteristics of OM in the colon of pigs (Becker et al., 2003). The technique can be adapted to obtain gas production profiles reflecting the fermentation of protein (N availability). To achieve this, incubations have to be done with an excess of fast fermentable carbohydrates, in an N-free environment making N the limiting factor for microbial growth depending on the availability of N from the feed samples. The aim of this study was to investigate the possibilities to use the gas production technique to determine the fermentation characteristics of protein in the hindgut of pigs.

Pharmacological levels of dietary copper (150–250 mg/kg) improve growth performance in pigs, but the majority of Cu is excreted in the manure and may contribute to accumulation in the soil. This experiment with 4 levels of dietary Cu supplementation (15, 80, 120, and 160 mg/kg) from weaning to d 56 after weaning was conducted to determine the dose-dependent effects of dietary Cu on growth performance and fecal consistency in pigs. From d 56 to slaughter, all pigs received the same grower and finisher diets supplemented with 15 mg/kg Cu. Each treatment comprised 10 pens with 8 pigs each, mixed males and females, as experimental units. The pigs were housed in a nursery unit until d 40 after weaning and in a grow–finish unit thereafter. Growth performance and fecal consistency were determined in 2-wk intervals until d 56; thereafter, growth performance was monitored between d 56 and slaughter. The Cu supplementation linearly increased ADFI and ADG (P < 0.001) until d 40 and linearly increased G:F (P < 0.01) until d 28 of the nursery period. Copper supplementation linearly increased ADG (P = 0.024) from d 40 to 56. The proportion of piglets with loose feces and diarrhea was reduced with incremental dietary Cu in each 2-wk interval until d 56. The combination of our data with 5 published studies in weaned pigs and subsequent regression analysis showed that the inclusion of the European Union maximum Cu supplement of 160 mg/kg enhances the ADG by approximately 14%. Reduction of the Cu supplement to 120 mg/kg would reduce the ADG by 2 to 3% and increase the number of piglets with loose feces. Pharmacological levels of dietary copper (150–250 mg/kg) improve growth performance in pigs, but the majority of Cu is excreted in the manure and may contribute to accumulation in the soil. This experiment with 4 levels of dietary Cu supplementation (15, 80, 120, and 160 mg/kg) from weaning to d 56 after weaning was conducted to determine the dose-dependent effects of dietary Cu on growth performance and fecal consistency in pigs. From d 56 to slaughter, all pigs received the same grower and finisher diets supplemented with 15 mg/kg Cu. Each treatment comprised 10 pens with 8 pigs each, mixed males and females, as experimental units. The pigs were housed in a nursery unit until d 40 after weaning and in a grow–finish unit thereafter. Growth performance and fecal consistency were determined in 2-wk intervals until d 56; thereafter, growth performance was monitored between d 56 and slaughter. The Cu supplementation linearly increased ADFI and ADG (P <0.001) until d 40 and linearly increased G:F (P <0.01) until d 28 of the nursery period. Copper supplementation linearly increased ADG (P = 0.024) from d 40 to 56. The proportion of piglets with loose feces and diarrhea was reduced with incremental dietary Cu in each 2-wk interval until d 56. The combination of our data with 5 published studies in weaned pigs and subsequent regression analysis showed that the inclusion of the European Union maximum Cu supplement of 160 mg/kg enhances the ADG by approximately 14%. Reduction of the Cu supplement to 120 mg/kg would reduce the ADG by 2 to 3% and increase the number of piglets with loose feces.</p

Dit onderzoek is uitgevoerd om de invloed te bepalen van de hoogte (15-160 mg/kg voer) en duur (2- 8 weken) van gebruik van een kopersupplement in het voer van gespeende biggen op de groeiprestaties, mestconsistentie en expressie van genen gerelateerd aan de koperabsorptie vanuit verschillende segmenten van de dunne darm.

Abstract Three in vitro experiments were carried out to determine the effect of temperature, moisture content, duration of incubation, Ca level, soaking with water or citric acid onphytate degradation in a wheat–barley–rye–soybean meal-based broiler diet. In experiment 1, phytase activity of individual feed ingredients and 4 low-P broiler diets, containing 2, 4, 8, and 12g Ca per kg diet, respectively, were measured in the presence or absence of sodium phytate or soybean meal. By using sodium phytate as substrate, phytase activity of rye, wheat, barley and soybean meal was 3350, 1170, 580 and 30FTU/kg, respectively (P<0.001). Calcium level had no effect on the activity of intrinsic phytase of diets (P>0.05). In experiment 2, the effect of 2 moisture levels (0.25 and 50%), 3 temperatures (70, 75 and 80̊C) and 3 durations of incubation (2, 4, and 8min) on the residual phytase activity of diet 1 (basal diet) were evaluated as a 2×3×3 factorial arrangement with 3 replicates per treatment. The loss of activity of intrinsic phytase increased from 0.25 at 70̊C to 0.61 at 80̊C (P<0.001). Increasing duration of incubation from 2min to 8min increased the loss of activity from 0.27 to 0.52 (P<0.001). By increasing the moisture content, loss of activity of intrinsic phytase also significantly increased from 0.25 at 25% moisture to 0.53 at 50% moisture. In experiment 3, the effects of 4 dietary Ca levels (2, 4, 8, and 12g/kg), 2 types of soaking (with water or citric acid solution) and 4 duration times of soaking (2, 4, 8 and 24h) on the amount of P released from the complete diet were determined as a 4×2×4 factorial arrangement with 3 replicates per treatment. Increasing Ca level of the diet from 2 to 12g/kg decreased the amount of released P from 1.19 to 0.97g/kg of diet (P<0.001). As time of soaking increased, the difference in released P due to soaking with citric acid comparison to soaking with deionized water became more prominent (interaction soaking×time; P<0.05). In conclusion, soaking of a broiler diet, especially in a citric acid solution one day before feeding, may increase available P and decrease the need of supplemental inorganic P to these diets, thus improving the sustainable use of P resources. Abbreviations: h, hour, min, minute, P, phosphorus, SPM, strokes per minute

A meta-analysis was conducted to determine the effect of microbial phytase in pig diets on digestibility and bioavailability of Cu and Zn. Studies (n = 22) into effects of microbial phytase on digestibility and plasma levels of Cu and Zn were included in a dataset and regression analysis was performed to quantify the effect of Aspergillus niger derived 3-phytase in studies (n = 14) with a maximum dietary Zn content of 100 mg/kg and a maximum Cu addition of 20 mg/kg. Phytase inclusion increased digestibility of Zn (P = 0.003) and plasma Zn content (P < 0.001) without affecting digestibility and plasma level of Cu. Based on a comparison with dose-response studies with Zn, we estimated 500 phytase units (FTU) of microbial phytase is equivalent to 27 mg of Zn from ZnSO4.

Complexation of dietary phytate with cations is a major cause of reduced bioavailability of Zn and possibly Cu in pig diets. We conducted 2 studies with 2 treatments in young growing pigs (8 to 40 kg) to estimate potential contributions of phytase to availability and supply of Zn and Cu, respectively. Each treatment comprised 10 pens with 8 pigs each as experimental units. In Exp. 1, 500 phytase units (FTU)/kg of microbial phytase (Natuphos 5000G; BASF) was added to a diet containing 15 mg Zn from ZnSO4 and 160 mg/kg Cu from CuSO4 in addition to Cu and Zn from feed ingredients. In Exp. 2, 500 FTU/ kg was added to a diet containing 45 mg Zn from ZnSO4 without added CuSO4. Feces were collected to determine nutrient digestibility, blood was collected, and pigs were killed to determine Cu and Zn in the liver. In both experiments, phytase inclusion increased (P < 0.001) Zn digestibility by on average 10% units, serum Zn level (P < 0.001) by 0.4 mg/L, and liver Zn content (P < 0.001) by 129 mg/kg DM. In Exp. 1 phytase increased (P = 0.03) Cu digestibility by 6% units but reduced (P = 0.04) liver Cu content by 35 mg/kg DM. In Exp. 2 phytase reduced (P < 0.001) Cu digestibility by 16% units without affecting liver Cu content. Results indicate that the effect of phytase on Cu availability depends on dietary Cu and Zn content and the response variable studied. In conclusion, the consistent effects of phytase on indices of Zn status allow a reduction of Zn inclusion in phytase-supplemented diets.

The standard Ca/aP ratio (2.2) can be recommended for application in practical diets. Based on the results of this experiment, no proof was found for our hypothesis that the development of the skeleton in fast growing broilers could not keep pace with the gain of the soft tissues. This experiment showed that the P requirement was not fulfilled with the low aP level in the diet. For determination of the optimal dietary aP level, however, a dose – response experiment should be performed.

In dit rapport wordt op basis van wetenschappelijke literatuur de behoefte aan koper en zink van groeiende varkens, fokzeugen en –beren besproken en een voorstel tot normstelling gedaan.