Influence of method of whole wheat inclusion and xylanase supplementation on the performance, apparent metabolisable energy, digestive tract measurements and gut morphology of broilers

1. The aim of the present study was to examine the influence of whole wheat inclusion and xylanase supplementation on the performance, apparent metabolisable energy (AME), digesta viscosity, and digestive tract measurements of broilers fed on wheat-based diets. The influence of the method of whole wheat inclusion (pre- or post-pelleting) was also compared. A 3 x 2 factorial arrangement of treatments was used with three diet forms (648 g/kg ground wheat [GW], GW replaced by 200 g/kg of whole wheat before [WW1] or after cold-pelleting [WW2]) and two xylanase levels (0 and 1000 XU/kg diet). 2. Birds given diets containing whole wheat had improved weight gains, feed efficiency and AME compared to those fed on diets containing ground wheat. The relative gizzard weight of birds fed WW2 diets was higher than in those fed GW and WW1 diets. Pre-pelleting inclusion of whole wheat had no effect on relative gizzard weight. Post-pelleting inclusion of whole wheat resulted in greater improvements in feed efficiency and AME than the pre-pelleting treatment. 3. Xylanase supplementation significantly improved weight gain, feed efficiency and AME, irrespective of the wheat form used. Viscosity of the digesta in the duodenum, jejunum and ileum were reduced by xylanase addition. Xylanase supplementation reduced the relative weight of the pancreas. 4. Neither xylanase supplementation nor whole wheat inclusion influenced the relative weight and length of the small intestine. 5. Xylanase supplementation increased ileal villus height. A significant interaction between diet form and xylanase was observed for ileal crypt depth. Xylanase supplementation had no effect on crypt depth in birds fed on diets containing GW, but increased the crypt depth in WW2 diets. No significant effects of diet form and xylanase supplementation were observed for the thickness of the tunica muscularis layer of gizzard or villus height, crypt depth, goblet cell numbers or epithelial thickness in the ileum. 6. Improved performance observed with post-pelleting inclusion of whole wheat was associated with increased size of the gizzard and improved AME. The gizzard development hypothesis, however, will not explain the improvements observed with pre-pelleting inclusion of whole wheat, suggesting the involvement of other factors.     

Influence of wheat-based diets supplemented with xylanase, bile acid and antibiotics on performance, digestive tract measurements and gut morphology of broilers compared with a maize-based diet

1. The aim of the present study was to compare wheat-based diets supplemented with arabinoxylanase, bile acid and virginiamycin with a maize-based diet in their effects on the performance of broilers. 2. The diets were fed to 5 groups of broilers. Group A received a maize-based diet (control), and groups B, C, D and E were fed on wheat-based diets. Diets C, D and E were supplemented with arabinoxylanase (150 mg/kg), bile acid (500 mg/kg) and virginiamycin (200 mg/kg), respectively. 3. A total of 450 1-d-old Ross 385 chicks were randomly divided into 5 groups, each with three pens as replicates (30 birds per pen). The experimental diets were given for 18 d. On d 18, three chickens from each group were slaughtered by cervical dislocation and the liver weight, and duodenal, jejunal and ileal lengths were measured for length and width of the villi and the height of crypts. 4. Arabinoxylanase, bile acid and virginiamycin supplementation significantly increased feed intake and daily gain but had no significant effect on feed conversion ratio. The liver weight was significantly greater in virginiamycin supplemented chicks as compared with those on the diet containing bile acid. 5. Virginiamycin inclusion increased full and empty caeca weight significantly compared with groups A and D. Group A had the lightest caeca. Significant effects of diets were observed on duodenal, ileal and intestinal length, but jejunal length was not affected by diet. The heights of duodenal and ileal, but not jejunal, villi were significantly affected by the treatments. The lengths of villi in groups B and E were significantly higher than other groups. The mean height of ileal villi in group A was significantly higher than in groups receiving the wheat-based diets. The mean width of duodenal and ileal villi was significantly affected by the ration. The height of crypts in group B was significantly higher than in group E. 6. It could be concluded that supplementation of the wheat-based broiler ration with virginiamycin had significant positive effects on gastrointestinal tract characteristics for absorption. Supplementation with bile acid reduced the weight of liver and caeca and the length of duodenum, jejunum, ileum and in small intestine and the height and width of villi.     

Influence of high dose of phytase and an emulsifier on performance,apparent metabolisable energy and nitrogen retention in broilers fed on diets containing soy oil or tallow

1. The effects of high dose of microbial phytase and an emulsifier on the performance, apparent metabolisable energy (AME) and nitrogen (N) retention in broilers fed on diets containing different fat sources were examined in a 5-week trial. Two fat sources (soy oil and tallow), two inclusion levels of E. coli phytase (500 or 1000 phytase units (FTU)/kg diet) and two inclusion levels of lysolecithin emulsifier (0 or 3.5 g/kg of diet) were evaluated in a 2 × 2 × 2 factorial arrangement of treatments.

2. Throughout the 5-week trial, soy oil supplementation improved weight gain and feed per gain compared with tallow, but had no effect on feed intake.

3. The high dose of phytase increased the weight gain and feed intake and lowered the feed per gain during d 1–21, but had no effect on performance parameters over the whole trial period.

4. An effect of emulsifier was observed for feed intake during d 1–21 and over the whole trial period. Addition of emulsifier increased feed intake compared with diets without emulsifier.

5. During weeks 1, 2, 3 and 5, birds fed on soy oil–based diets had higher nitrogen-corrected AME (AME_N) compared with those fed on tallow-based diets. During weeks 2, 3 and 5, the effect of phytase was significant for AME_N, with the high dose increasing the AME_N. During week 2, AME_N was increased with emulsifier addition.

6. During weeks 1, 2, 3 and 5, birds fed on soy oil–based diets had higher fat retention compared with those fed on tallow-based diets. The high dose of phytase improved the retention of fat during week 5 and the addition of emulsifier resulted in higher fat retention during week 1.

7. During weeks 2, 3 and 5, an interaction between fat source × phytase × emulsifier was observed for N retention. In soy oil–based diets, emulsifier plus 1000 FTU/kg phytase increased N retention compared with other groups, while in tallow-based diets, emulsifier addition increased N retention in diets with 500 FTU/kg, but not in 1000 FTU/kg diet.

8. Overall, the present data suggest that the dietary fat source influenced performance, AME_N and fat retention in broiler chickens. There is opportunity to improve bird performance during d 1–21, AME_N and fat retention with higher doses of microbial phytase. Addition of the emulsifier increased the AME_N during week 2 and tract retention of fat during week 1, but this effect was not translated into improvements in performance.

     

Effects of individual or combined xylanase and phytase supplementation on energy, amino acid, and phosphorus digestibility and growth performance of grower pigs fed wheat-based diets containing wheat millrun

The objective of these studies was to determine if dietary enzymes increase the digestibility of nutrients bound by nonstarch polysaccharides, such as arabinoxylans, or phytate in wheat millrun. Effects of millrun inclusion rates (20 or 40%), xylanase (0 or 4,375 units/kg of feed), and phytase (0 or 500 phytase units/kg of feed) on nutrient digestibility and growth performance were investigated in a 2 x 2 x 2 factorial arrangement with a wheat control diet (0% millrun). Diets were formulated to contain 3.34 Mcal of DE/kg and 3.0 g of true ileal digestible Lys/Mcal of DE and contained 0.4% chromic oxide. Each of 18 cannulated pigs (36.2 +/- 1.9 kg of BW) was fed 3 diets at 3x maintenance in successive 10-d periods for 6 observations per diet. Feces and ileal digesta were collected for 2 d. Ileal energy digestibility was reduced (P < 0.01) linearly by millrun and increased by xylanase (P < 0.01) and phytase (P < 0.05). Total tract energy digestibility was reduced linearly by millrun (P < 0.01) and increased by xylanase (P < 0.01). For 20% millrun, xylanase plus phytase improved DE content from 3.53 to 3.69 Mcal/kg of DM, a similar content to that of the wheat control diet (3.72 Mcal/kg of DM). Millrun linearly reduced (P < 0.01) ileal digestibility of Lys, Thr, Met, Ile, and Val. Xylanase improved (P < 0.05) ileal digestibility of Ile. Phytase improved ileal digestibility of Lys, Thr, Ile, and Val (P < 0.05). Millrun linearly reduced (P < 0.05) total tract P and Ca digestibility and retention. Phytase (P < 0.01) and xylanase (P < 0.05) improved total tract P digestibility, and phytase and xylanase tended to improve (P < 0.10) P retention. Phytase improved Ca digestibility (P < 0.05) and retention (P < 0.01). The 9 diets were also fed for 35 d to 8 individually housed pigs (36.2 +/- 3.4 kg of BW) per diet. Millrun reduced (P < 0.05) ADFI, ADG, and final BW. Xylanase increased (P < 0.05) G:F; phytase reduced (P < 0.05) ADFI; and xylanase tended to reduce (P = 0.07) ADFI. In summary, millrun reduced energy, AA, P, and Ca digestibility and growth performance compared with the wheat control diet. Xylanase and phytase improved energy, AA, and P digestibility, indicating that nonstarch polysaccharides and phytate limit nutrient digestibility in wheat byproducts. The improvement by xylanase of energy digestibility coincided with improved G:F but did not translate into improved ADG.     

Influence of conditioning temperature on the performance, nutrient utilisation and digestive tract development of broilers fed on maize- and wheat-based diets

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.     

小麦型日粮添加木聚糖酶和植酸酶对肉鸡生长性能、回肠氨基酸表观消化率及常量元素沉积的影响

本文旨在研究小麦型日粮中添加木聚糖酶和植酸酶对肉鸡生长性能、回肠氨基酸表观消化率及矿物元素沉积的影响。试验选择1日龄科宝白羽肉仔鸡850只,随机分成5组,每组5个重复,每个重复34只鸡。一共有5种日粮,即低磷日粮、高磷日粮、低磷日粮+2000 IU/kg木聚糖酶、低磷日粮+500 FTU/kg植酸酶,低磷日粮+2000 IU/kg木聚糖酶+500 FTU/kg植酸酶,试验进行21 d。低磷组较高磷组显著降低了肉鸡的日增重、日采食量及趾骨灰分含量(P <0.05),与低磷组相比,木聚糖酶组显著降低了肉鸡的料比(P <0.05),而植酸酶组显著提高了肉鸡日增重、日采食量、趾骨灰分及饲料利用率(P <0.05)。复合酶组显著提高了15种氨基酸回肠表观消化率(P <0.05)。与低磷组相比,木聚糖酶组显著提高了表观消化能和可消化代谢能及回肠氮消化率(P <0.05),而植酸酶显著提高了氮沉积及回肠氮消化率(P <0.05),复合酶组显著提高了代谢能、可消化代谢能及氮沉积量(P <0.05)。植酸酶和复合酶组较高磷组显著提高了磷表观消化率和沉积量(P <0.05),但低磷组较高磷组显著提高了钙的表观消化率(P <0.05),植酸酶酶和复合酶组较其他3组显著提高了钾的沉积量(P <0.05)。结论 :小麦型日粮同时添加植酸酶和木聚糖酶对肉鸡生长和消化的影响要优于单独添加这两种酶。     

Influence of pellet diameter and length on the quality of pellets and performance,nutrient utilisation and digestive tract development of broilers fed on wheat-based diets

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.     

Influence of a microbial phytase on the performance and the utilisation of energy,crude protein and fatty acids of young broilers fed on phosphorus-adequate maize- and wheat-based diets

1. The effects of microbial phytase on the performance and nutrient utilisation in broilers fed on phosphorus-adequate starter diets were examined in this study. The effect of phytase on the apparent ileal digestibility of fatty acids was of particular interest. Two grain types (maize and wheat) and two inclusion concentrations of a phytase enzyme from Escherichia coli expressed in Schizosaccaromyces pombe (0 or 500 phytase units (FTU)/kg of feed) were evaluated in a 2 × 2 factorial arrangement of treatments.

2. Supplemental phytase improved the weight gain and feed per gain, but had no effect on the feed intake of young broilers receiving phosphorus-adequate diets.

3. Phytase supplementation improved the apparent ileal digestibility of nitrogen and phosphorus in both diet types. Phytase supplementation tended to improve the apparent ileal digestible energy in wheat-based diets, but had no effect on the apparent metabolisable energy in both diet types.

4. Supplementation of phytase increased the apparent ileal digestibility of fat, with similar effects for the different fatty acids measured. Increments on ileal fat digestibility due to phytase were not dependent on the type of diet.

5. Dietary supplementation of microbial phytase enhanced not only the digestibility of phosphorus, but also that of nitrogen and fat, exhibiting increased ileal digestibility for all fatty acids in P-adequate maize- and wheat-based diets.     

Effects of microbial phytase, produced by solid-state fermentation, on the performance and nutrient utilisation of broilers fed maize- and wheat-based diets

1. The influence of a microbial phytase on the performance, toe ash contents and nutrient utilisation of male broilers fed diets based on maize and wheat was investigated. The experiment was conducted as 2 x 2 x 2 factorial arrangement of treatments. Within the factorial, two diet types (maize-soy or wheat-soy) containing two levels of non-phytate phosphorus (3.0 or 4.5 g/kg) were evaluated and each level of non-phytate phosphorus was supplemented with 0 or 500 PU phytase/kg diet. Each of the 8 dietary treatments were fed to 6 pens of 8 birds from d 1 to 21 post-hatching. 2. Main effects of diet type and phytase were observed for all parameters. Main effect of non-phytate phosphorus was significant only for feed/gain and toe ash contents. Phytase addition improved weight gains irrespective of diet type or non-phytate phosphorus level, but the magnitude of improvement in the phosphorus-deficient wheat-soy diet was greater, resulting in a diet type x non-phytate phosphorus interaction. Responses in toe ash contents were noted only in phosphorus-deficient diets, as indicated by a non-phytate phosphorus x phytase interaction. 3. Phytase addition improved apparent metabolisable energy values of wheat-based diets, but had little effect on the apparent metabolisable energy of maize-based diets as shown by a diet type x phytase interaction. The apparent metabolisable energy was not influenced by dietary non-phytate P. 4. Phytase improved ileal nitrogen digestibility in both diet types, but the responses to added phytase tended to be higher in wheat-based diets, as shown by a diet type x phytase interaction. 5. Increasing the dietary non-phytate phosphorus level reduced phosphorus digestibility and increased excreta phosphorus content. Addition of phytase improved phosphorus digestibility, but the increments were higher in low phosphorus diets resulting in a non-phytate phosphorus x phytase interaction. Phytase addition tended to lower the excreta phosphorus content, but the effects were greater in birds fed low phosphorus diets, as shown by a non-phytate phosphorus x phytase interaction.     

Dietary soluble non-starch polysaccharide level and xylanase supplementation influence performance,egg quality and nutrient utilization in laying hens fed wheat-based diets

The aim of this study was to evaluate the effects of dietary soluble non-starch polysaccharide (sNSP) content and xylanase supplementation on production performance, egg quality parameters, and nutrient digestibility in Hy-line Brown layers from 25 to 32 wk of age. A total of 144 Hy-line Brown laying hens (25 wk of age) were randomly allocated to 1 of 4 wheat-based dietary treatments in a 2 × 2 factorial experimental design, with 36 replicates of individual hens per treatment. The diets were formulated to contain either a high or low sNSP level (at 13.3 or 10.8 g/kg) and were supplemented with either 0 or 12,000 BXU/kg exogenous xylanase. Birds were fed these treatment diets for an 8-wk period, and hen production performance, including daily egg production, average egg weight, daily egg mass, feed conversion ratio and proportion of dirty and abnormal eggs were measured at bird age 25 to 28 wk and 29 to 32 wk. An interaction between sNSP content of the diet and xylanase supplementation was observed on daily egg production from 25 to 28 wk of age (P = 0.018); birds fed the high sNSP diet without xylanase had lower egg production than those fed any other treatment. An interaction between the 2 dietary factors was also observed on hen weight gain at 29 to 32 wk of age (P = 0.014), with birds fed the low sNSP diet with 12,000 BXU/kg xylanase presenting greater weight gain compared to those fed the high sNSP diet with 12,000 BXU/kg xylanase. Feed intake at 29 to 32 wk of age was reduced by xylanase supplementation (P = 0.047). Xylanase supplementation also increased yolk colour score at both 28 and 32 wk of age, and decreased yolk weight at 32 wk of age (P = 0.014, 0.037 and 0.013, respectively). Birds fed the low sNSP diet presented lower protein digestibility (P = 0.024) than those fed the high sNSP diet. Additionally, birds fed high sNSP presented higher shell reflectivity at both 28 and 32 wk of age (P = 0.05 and 0.036, respectively). The influence of duration of feeding the treatment diets on egg quality was also determined. It was observed that egg weight, yolk weight and yolk colour score consistently increased over time, regardless of experimental treatment effects. In contrast, Haugh Unit and albumen height significantly decreased throughout the study period in all treatments, although this was less pronounced in hens fed the treatment with high sNSP and no supplemental xylanase. A reduction in shell breaking strength over time was observed only in hens fed the treatments without xylanase addition, and shell thickness was improved over time only in birds fed the low sNSP diet with xylanase. The impacts of the dietary treatments were largely inconsistent in this study, so a solid conclusion cannot be drawn. However, these findings do indicate that dietary NSP level influences layer production performance, and thus should be considered when formulating laying hen diets. It also proved that further research is warranted into how to optimize the benefits of xylanase application in laying hens.     

Effect of high-dose phytase and citric acid,alone or in combination,on growth performance of broilers given diets severely limited in available phosphorus

1. Two trials were conducted to evaluate the effect of high-dose phytase alone or in combination with citric acid (CA) in the diet severely limited in available phosphorus (P) on performance, plasma P and plasma Ca of broilers from 22 to 42 d of age.

2. In Trial 1, 297 21-d-old female chicks were placed into 27 pens and allocated to 9 maize-soybean meal-based dietary treatments, which were a positive control [PC, 4.23 g/kg non-phytate P (NPP)] and 8 negative control (NC, 1.35 g/kg NPP) groups consisting of two concentrations of CA (0 and 20 g/kg) and 4 concentrations of phytase (0, 1000, 2000 and 4000 U/kg) in a 2 × 4 factorial arrangement. In Trial 2, 192 21-d-old male chicks were placed into 24 pens and allocated to 6 wheat-canola meal-based dietary treatments, which were a PC (4.2 g/kg NPP), a NC (1.68 g/kg NPP) and 4 NC groups consisting of two concentrations of CA (0 and 20 g/kg) and two concentrations of phytase (2000 and 4000 U/kg) in a 2 × 2 factorial arrangement.

3. In both trials, birds fed on the PC had significantly higher average daily gain (ADG), average daily feed intake (ADFI), plasma P and lower feed conversion ratio (FCR) and plasma Ca than those of birds fed on the NC. CA supplementation significantly increased ADG and ADFI. There was a significant interaction between CA and phytase on plasma P where CA improved the effect of phytase on plasma P. In Trial 1, phytase addition improved ADG, ADFI, FCR and plasma Ca linearly.

4. Briefly, this research showed the interaction effect between CA and phytase on plasma P when broilers were fed on diets based on maize-soybean meal or wheat-canola meal. The results showed that CA supplementation lowered the concentration of phytase that is needed in low NPP diets to increase plasma P.     

Comparison of two direct bioassays using 3-week-old broilers to measure the metabolisable energy of diets containing cereals high in fibre: differences between true and apparent metabolisable energy values

1. Nitrogen-corrected apparent and true metabolisable energy contents (AMEN and TMEN) of 12 diets, containing different amounts of maize, wheat, barley and rye, barley with beta-glucanase and maize with 0.05 g/kg guar gum were measured using 3-week-old male broilers. 2. The AMEN method involved: 4 d of dietary adaptation, 24 h of starvation, 54 h of ad libitum feeding, 24 h of starvation and daily total droppings collection. TMEN was measured after a 48 h starvation period followed by 2 d of tube-feeding two doses of 15 g of the diets and quantitatively collecting all the droppings after 48 h of starvation. The endogenous energy losses (EELN) were measured after tube-feeding 8 chickens with 30 g of glucose, also over 2 d. 3. The results show that a significant interaction exists between the nature of the diets and the method used to measure metabolisable energy. Differences between TMEN and AMEN values ranged from 1.03 to 1.98 MJ/kg dry matter. These differences were positively correlated with the total pentosan contents of the diet (r = 0.94), the natural logarithm of the viscosities of the water extracts (r = 0.87), the sum of the contents of total pentosans and total beta-glucan (r = 0.85), the calculated total non-starch polysaccharide contents (r = 0.79), the neutral detergent fibre contents (r = 0.76) and the total beta-glucan contents (r = 0.70). Furthermore, a significant interaction was found between diets and the method used to derive lipid digestibility. The differences between apparent and true lipid digestibility ranged from 0.05 percentage points for the wheat diet to 0.20 percentage points for the rye diet. 4. From the results of this trial, it appears that TMEN overestimates the energy value of high fibre diets.     

Influence of an organic acid blend and essential oil blend,individually or in combination,on growth performance,carcass parameters,apparent digestibility,intestinal microflora and intestinal morphology of broilers

1. This study aimed to evaluate the influence of an organic acid (OA) and essential oil (EO) blends, individually or in combination, on growth performance, carcass parameters, apparent digestibility, intestinal microflora and intestinal morphology of broilers.

2. A total of 480 one-d-old male Ross 308 chicks were randomly assigned to 4 treatments consisting of 4 replicates each (n = 30 birds in each replicate). Dietary treatments consisted of a basal diet (control), and basal diet supplemented with 2 g/kg OA blend (OAB), 300 mg/kg EO blend (EOB), or with 2 g/kg OA and 300 mg/kg EO blend (OAB–EOB) for 42 d.

3. The dietary supplementation with EO blend or in combination with OA blend increased body weight gain and improved feed efficiency as compared to control. Dietary treatments had no significant effects on feed consumption or relative organ weights of broilers.

4. The OAB diet increased carcass yield compared to the control diet but the lowest carcass yield occurred with the OAB–EOB combination. Birds fed on EOB and OAB–EOB diets had lower ileum Escherichia coli counts than birds fed on the control diet.

5. There was no significant effect of treatments on apparent digestibility at 16–21 d but the EOB and OAB–EOB diets increased apparent digestibility of dry matter and crude protein during the finisher period (d 37–42) compared to the control diet.

6. Birds fed on the EOB and OAB–EOB diets had greater villus height in the ileum at 21 and 42 d of age and had lower crypt depth in the ileum at 42 d of age than birds given the control diet.

7. In conclusion, beneficial effects of the use of EO blend individually or in combination with the OA blend were observed but the OA blend alone was ineffective. Furthermore, the use of the combination of OA and EO was more effective, in some respects, than their individual use.

     

Effects of exogenous xylanase on performance,nutrient digestibility,volatile fatty acid production and digestive tract thermal profiles of broilers fed on wheat- or maize-based diet

1. A previous experiment reported that caecal temperature was negatively correlated with d 49 feed conversion ratio (FCR). This increased temperature in the caeca may indicate a prebiotic effect. An experiment was designed to investigate whether caecal temperature was affected in diets based on maize and whether other portions of the tract were affected.

2. A total of 25 Ross 308-d-old male broilers were allocated to each of 8 replicate pens per treatment. Treatments followed a 2 × 3 factorial design: two diets based on wheat or maize and three levels of enzyme addition, 0, 16 000 or 32 000 BXU/kg. Growth performance was assessed between d 1 and 49. Digestibility measurements were taken at d 28 and 49. On d 49, the excised small and large intestine of each bird was thermally imaged, weighed and volatile fatty acids (VFA) measured.

3. On d 28 and d 49, birds on the maize diets had higher feed intake and weight gain than those offered wheat diets. Additionally, on d 28, birds that received the maize diet had lower FCR than those offered the wheat diet. Enzyme improved FCR at d 49, independently of cereal. On d 28, enzyme improved the coefficient of apparent ileal DM digestibility and the coefficient of apparent ileal nitrogen digestibility. Enzyme only improved apparent ileal digestible energy in wheat-based diets (interactive term). On d 49, all digestibility parameters were improved by enzyme. Enzyme increased gizzard weight in maize-fed birds and the caeca of those fed wheat were heavier. The higher enzyme dose decreased duodenal temperature. In summary of VFA data, wheat-based diets produced more total VFAs and the total amount also increased with enzyme.

4. It appears from this study that there is equal potential in both wheat and maize diets for xylanase to improve performance of broilers probably through different mechanisms.     

Effects of dietary boron and phytase supplementation on growth performance and mineral profile of broiler chickens fed on diets adequate or deficient in calcium and phosphorus

1. Two experiments were designed to determine the effect of dietary boron (B) in broiler chickens. In Experiment 1, a 2 × 4 factorial arrangement of treatments was used to investigate the effect of dietary calcium (Ca) and available phosphorus (aP) (adequate or deficient) and supplemental B (0, 20, 40, and 60 mg/kg diet). In Experiment 2, B, at 20 mg/kg, and phytase (PHY) (500 FTU/kg diet) were incorporated into a basal diet deficient in Ca and aP, either alone or in combination.

2. The parameters that were measured were growth performance indices, serum biochemical activity as well as ash and mineral (i.e. Ca, P, Mg, Fe, Cu and Zn) content of tibia, breast muscle and liver.

3. Results indicated that both supplemental B and dietary Ca and aP had marginal effects on performance indices of chickens grown for 42 d.

4. There were positive correlations (linear effect) between B concentrations of serum, bone, breast muscle and liver and the amount of B consumed.

5. Serum T₃ and T₄ activities increased linearly with higher B supplementation.

6. Increasing supplemental B had significant implications on breast muscle and liver mineral composition. Lowering dietary Ca and aP level increased Cu content in liver and both Fe and Zn retention in breast muscle. Tibia ash content and mineral composition did not respond to dietary modifications with either Ca–aP or B.

7. The results also suggested that dietary contents of Ca and aP do not affect the response to B regarding tissue mineral profile. Dietary combination with B and PHY did not create a synergism with regard to growth performance and bioavailability of the minerals.     

The effects of xylanase supplementation on growth, digestion, circulating hormone and metabolite levels, immunity and gut microflora in cockerels fed on wheat-based diets

1. The xylanase product used in this study was derived from a genetically modified isolate of Aspergillus niger. Two trials were conducted to investigate the effects of xylanase supplementation on growth, digestion, circulating hormone and metabolite levels, immune parameters and composition of the gut microflora in cockerels fed on wheat-based diets. 2. The experimental diets consisted of a wheat-based control diet supplemented with 0 or 0.1% enzyme preparation. The diets were fed between 7 and 21 d of age. 3. Enzyme supplementation improved growth and feed conversion efficiency. The addition of enzyme to wheat-based diet increased the apparent total digestibility of dry matter (DM), crude protein and fat. 4. Enzyme supplementation reduced the relative weight of digestive organs to a certain extent, but there was no significant difference. Enzyme supplementation reduced digesta viscosity in the jejunum. There was no significant difference between the two experimental groups in counts of lactobacillus and coliform bacteria in the caeca. 5. Enzyme supplementation increased the concentration of blood thyroxine (T(4)), insulin-like growth factor I (IGF-I) and insulin, reduced the concentrations of blood uric acid, but had no significant effect on the concentrations of blood glucose and triiodothyronine (T(3)). 6. Enzyme supplementation increased the relative weight of spleen of cockerels, serum antibody titres to Newcastle disease virus (NDV), lymphocyte proliferation in response to phytohaemagglutinin (PHA) and the natural killer (NK) cell activity. 7. It is concluded that supplementation with an enzyme preparation (xylanase), which hydrolyses non-starch polysaccharides can improve growth in cockerels fed on wheat-based diets. This improvement is achieved through enzyme effects on digestion, absorption, metabolism and immunity of cockerels.     

The effect of short-term phytase supplementation on the apparent total tract digestibility of calcium and phosphorus and the reproductive performance of late gestation and lactating sows fed diets without mineral phosphorus

The objective of this study was to measure apparent total tract digestibility (ATTD) of Ca and P as well as reproductive performance in late gestation and lactating sows supplemented with a novel phytase and to compare the response to phytase supplementation between late gestation and lactating sows. A total of 45 late gestation sows and 45 lactating sows were used in experiments 1 and 2, respectively, in a completely randomized design. The sows were provided with a control diet or the control diet supplemented with 187.5 or 375 FYT phytase/kg feed for 10 days. The diets were prepared according to the formulas in use for production but without any inorganic P supplement. Titanium dioxide was included at 3 g/kg feed as an indigestible marker. Each dietary treatment was replicated with 15 sows individually housed in farrowing stalls. The sows were allowed to adapt to the experimental diets for 5 days before a 5-d fecal collection by grab sampling, and the performance of the sows and their litters were measured until weaning. The results showed that the ATTD of Ca increased linearly (P < 0.001), while the ATTD of P increased both linearly and quadratically (P < 0.01) with increasing supplementation of phytase in both late gestation and lactating sows. There was no significant effect of phytase on the ATTD of dry matter, crude protein, and gross energy, and the performance of the sows and their progenies. The phytase added at 187.5 and 375 FYT/kg feed released 0.07% and 0.10% digested P, respectively, in late gestation sows, which compared with 0.09% and 0.12% digested P in lactating sows. In conclusion, a novel phytase at 187.5–375 FYT/kg feed could release 0.07–0.12% digestible P for sows. It appeared that using the P digestibility values of feed ingredients listed by NRC to formulate a diet for sows might overestimate dietary P supply and a greater response to phytase supplementation could be expected in lactating sows than in late gestation sows.     

低能日粮添加木聚糖酶或复合酶对肉鸡生产性能和养分消化率的影响

试验旨在研究肉鸡低能日粮中添加木聚糖酶或复合酶对肉鸡生产性能和养分消化率的影响。采用单因子的试验设计,试验分6个处理,每个处理8个重复,每重复10只肉仔鸡。6个试验饲粮处理分别为正对照组(PC)、负对照组(NC,在正对照组基础上降低表观代谢能836 kJ/kg)、以及4个在NC基础上的加酶组(分别为处理1:木聚糖酶添加量为4 000 U/kg饲料;处理2:木聚糖酶、α-淀粉酶和蛋白酶分别为300 U/kg、400 U/kg和4 000 U/kg饲料;处理3:木聚糖酶、α-淀粉酶和蛋白酶分别为:1383U/kg6、7U/kg和667U/kg;处理4:木聚糖酶、α-淀粉酶和蛋白酶分别为2 766 U/kg、134 U/kg和1 334 U/kg)。试验结果表明,与PC相比,NC降低了肉鸡的增重、提高了料肉比(P<0.05);与NC相比,4个加酶组提高增重3%~10%和改善料肉比2%~8%(P<0.05),加酶后NC组肉鸡的生产性能达到了PC水平。NC降低了干物质、粗蛋白和能量的表观消化率(P<0.05),加酶组对养分消化率具有提高作用,且达到了PC水平;木聚糖酶和复合酶两种酶制剂对肉鸡生产性能和养分消化率的影响差异不显著,处理3和4两组间差异不显著(P>0.05)。结果表明,在降低代谢能836 kJ/kg的肉鸡饲粮中添加木聚糖酶或复合酶,能够使肉鸡的生产性能和养分消化率得以补偿,低能负对照饲粮加酶后能够使肉鸡的生产性能达到与正对照组相同水平。