Supplementation of broiler diets with high levels of microbial protease and phytase enables partial replacement of commercial soybean meal with raw,full‐fat soybean

A 3 × 3 + 1 factorial, involving three levels of protease (0, 15,000 or 30,000 PROT/kg) and three levels of phytase (1,000, 2,000 or 3,000 FYT/kg), was used to evaluate the effect of replacing commercial soybean meal (SBM) with raw, full‐fat soybean (RFSB) at 75 g/kg of diet for broilers. A control diet was used for comparison. Each treatment was replicated six times, with nine birds per replicate. The concentration of trypsin inhibitors (TIs) in the test diets was approximately 10,193.4 TIU/kg. Regardless of enzyme supplementation, feed intake (FI) and body weight gain (BWG) of birds in the control group were superior to those on the test diets. Birds that received the protease‐free test diets had reduced FI and BWG, but when supplemented with protease, were similar to the control diet in BWG, FI (except 0–35 days) and feed conversion ratio (FCR). When the test diet was supplemented with elevated levels (extradose) of protease and phytase, the BWG was improved during 0–10 days (p = .05) and 0–24 days (p < .01). Regardless of protease supplementation, the weight of thighs was lower for birds fed the test diets. Birds that received the control diet had smaller weight of pancreas. Increasing the level of phytase supplementation reduced (p < .05) the weight of the pancreas. The apparent ileal digestibility (AID) of CP and AA was higher in birds on the control diets, but this was also improved in test diets by protease supplementation. The activities of trypsin (7%), general proteolytic (11%) and lipase (12%) were slightly increased because of protease supplementation. Mucosal depth and apparent villus surface areas were increased by about 2.9% and 20%, respectively, due to supplementation of elevated level of phytase. It can be concluded that RFSB could partially replace SBM in broiler diets, provided the diets are supplemented with elevated levels of protease and phytase.     

Effects of supplementing freeze-dried Mitsuokella jalaludinii phytase on the growth performance and gut microbial diversity of broiler chickens

Inclusion of phytase in animal feedstuff is a common practice to enhance nutrients availability. However, little is known about the effects of phytase supplementation on the microbial ecology of the gastrointestinal tract. In this study, freeze-dried Mitsuokella jalaludinii phytase (MJ) was evaluated in a feeding trial with broilers fed a low available phosphorus (aP) diet. A total of 180 male broiler chicks (day-old Cobb) were assigned into three dietary treatments: Control fed with 0.4% (w/w) of available phosphorus (aP); Group T1 fed low aP [0.2% (w/w)] supplemented with MJ; and T2 fed low aP and deactivated MJ. The source of readily available P, dicalcium phosphate (DCP), was removed from low aP diet, whereby additional limestone was provided to replace the amount of Ca normally found in DCP. For each treatment, 4 replicate pens were used, where each pen consisted of 15 animals. The animals' energy intake and caecal bacterial community were monitored weekly for up to 3 weeks. The apparent metabolizable energy (AME) and apparent digestibility of dry matter (ADDM) of broilers fed with different diets were determined. In addition, the caecal microbial diversities of broilers were assessed using high-throughput next-generation sequencing targeting the V3-V4 region of bacterial 16S rRNA. The results showed that broilers fed with T1 diet have better feed conversion ratio (FCR) when compared to the Control (p < .05) and T2 diets (p < .05), demonstrating the efficiency of MJ as a supplement to low aP diet. Nevertheless, MJ did not significantly affect the microbial population and diversity in broilers' caeca, which mainly consists of members from Bacteroidetes, Firmicutes, and Proteobacteria. Regardless, significant variations in the caecal bacterial composition were observed over time, probably due to succession as the broilers aged. This is the first reported study on the effect of MJ on the microbial diversity of broiler's caeca.     

Effects of enzymatic hydrolysate of locust bean gum on digestibility,intestinal morphology and microflora of broilers

To investigate the effects of different levels of enzymatic hydrolysate of dietary locust bean gum on nutrient digestibility, intestinal morphology and microflora of broilers, a total of 768 one-day-old Arbor Acres (AA) broiler chicks were randomly divided into 6 treatments with 8 replicates per treatment and 16 birds per replicate. The treatments were as follows: (1) CON, basal diet; (2) ANT, basal diet +62.5 mg/kg flavomycin; (3) LBG, basal diet +0.1% locust bean gum; (4) ELBG-0.1, basal diet +0.1% enzymatic hydrolysate of LBG; (5) ELBG-0.2, basal diet +0.2% enzymatic hydrolysate of LBG; and (6) ELBG-0.3, basal diet +0.3% enzymatic hydrolysate of LBG. The digestibilities of ether extract, crude protein and dry matter were increased (p < .01) in broilers fed the ELBG-0.3 diet compared with the CON and LBG diets on day 21. Duodenal villus height and the ratio of the villus height to crypt depth were greater (p < .01) in broilers fed the ELBG-0.3 diet than the CON, ANT and LBG diets. Jejunum villus height was higher (p < .05) in broilers fed the ELBG-0.2 and ELBG-0.3 diets than the CON diet. The number of caecal Escherichia coli was reduced (p = .01) in broilers fed the ELBG-0.2 and ELBG-0.3 diets compared with the CON diet. The number of caecal Lactobacilli was greater (p < .05) in broilers fed the ELBG-0.3 diet than the CON and ANT diets. In summary, the addition of 0.3% locust bean enzymatic hydrolysate can increase the surface area of intestinal villi and the number of beneficial bacteria, inhibit the proliferation of harmful bacteria, maintain the balance of intestinal microflora and improve the digestibility of nutrients.     

Physiological and health‐related response of broiler chickens fed diets containing raw,full‐fat soya bean meal supplemented with microbial protease

A 2 × 3 factorial study (protease: 0 or 1,5000 PROT/kg and raw full‐fat soya bean meal [RSBM] replacing the commercial SBM at 0, 45 and 75 g/kg of diet) was conducted to examine the performance of broilers. Phytase (2000 FYT/kg) was uniformly added to each diet, each also replicated six times, with eight birds per replicate. Birds were raised in climate‐controlled rooms using sawdust as the bedding material and offered starter, grower and finisher diets. Feed intake (FI) and body weight gain (BWG) were reduced (p < .05) due to increasing levels of RSBM, but feed conversion ratio (FCR; 0–35 days) was unaffected. Over the first 24 days, neither RSBM nor protease supplementation affected (p > .05) mortality, footpad dermatitis or intestinal lesions in birds. At day 24, the weight, length, width and strength of tibia bone were reduced in chickens that received an elevated level of RSBM (75 g/kg of diet), but this was not significant at day 35. At day 24 (p < .05) and 35 (p < .01), Ca concentration in the litter was reduced when the RSBM level was increased in the diet, but P content was not affected. On days 24 (p < .05) and 35 (p < .01), the N content in litter was also increased with increase in dietary RSBM. Protease supplementation increased (p < .05) the uric acid concentration in the litter (at day 35), but the reverse was the case for ammonia concentration. Overall, the results of this study indicate that there are no major health‐related risks, associated with the replacement of commercial SBM with RSBM (≤25%) in broiler diets.     

Effects of chestnut tannins on intestinal morphology,barrier function,pro‐inflammatory cytokine expression,microflora and antioxidant capacity in heat‐stressed broilers

A study was conducted to evaluate the effects of chestnut tannins (CT) on intestinal morphology, barrier function, pro‐inflammatory cytokine expression, microflora and antioxidant capacity in heat‐stressed broilers. Four hundred 28‐day‐old male Ross 308 broilers were randomly assigned into four groups, with 10 replicates per group and 10 broilers per replicate. The broilers in the normal (NOR) group were kept at 22 ± 1°C and fed the basal diet, and each of the other three groups were treated with cyclic heat (33 ± 1°C from 0800 to 1800 and 22 ± 1°C from 1800 to 0800) and fed the basal diet with 0 (HT), 1 (CT1) or 2 (CT2) g of CT/kg of diet. The experiment lasted for 14 days. Compared with the HT group, broilers in the NOR and CT2 groups had higher (p < .05) average daily gain and villus height in the jejunum and lower serum d ‐lactate (p < .001) and diamine oxidase (p < .01) levels. The addition of 2 g CT/kg of diet increased the total antioxidant capacity (p < .001) and superoxide dismutase activities (p < .05) and zonula occludens‐1 mRNA expression level (p < .05) and decreased the malondialdehyde concentration (p < .01) and mRNA expression levels of interleukin‐6 (p < .001) and nuclear factor kappa B (p < .001) in the jejunal mucosa of heat‐stressed broilers. The populations of Escherichia coli and Clostridium in the jejunum (p < .01) and caecum (p < .05) of broilers in the HT group were higher than those in the NOR and CT2 groups. In conclusion, the addition of 2 g CT/kg of diet seemed to be a feasible means of alleviating the negative effects of heat stress on the growth performance and intestinal function of broilers.     

Effects of yeast cultures with different fermentation times on the growth performance,caecal microbial community and metabolite profile of broilers

The objective of this study was to investigate the effects of yeast culture (YC) on the growth performance, caecal microbial community and metabolic profile of broilers. A total of 350 1-day-old healthy Arbor Acres broilers were randomly assigned to seven treatment groups. The first group received a basal diet without YC supplementation, whereas the remaining groups received a basal diet supplemented with either YC fermented for 12, 24, 36, 48 or 60 hr, or a commercial YC product (SZ2). MiSeq 16S rRNA high-throughput sequencing was used to investigate the bacterial community structure, and gas chromatography–mass spectrometry was used to identify the metabolites in the caeca of broilers. The broilers that received a diet supplemented with YC had a higher average daily gain and average daily feed intake than those received YC-free or SZ2-enriched diets. The feed conversion ratio (FCR) of YCs fermented for 24 hr resulted in the best feed efficiency, whereas the FCR of YC fermented for 60 hr resulted in poor feed efficiency (p < .05). In the caeca of broilers, the bacterial communities were well separated, as determined by principal component analysis, and the proportions of the eight genera were significantly different among the seven groups (p < .05). The genus Akkermansia was the most abundant when the diet supplemented with YC fermented for 24 hr (p < .05). Furthermore, the Firmicutes/Bacteroidetes ratio was positively correlated with the FCR in the caecum (r = .47, p < .005). Five differentially expressed metabolites (i.e., L-alanine, benzeneacetic acid, D-mannose, D-arabitol and cholesterol) were identified in the caeca of broilers that received diets supplemented with YCs fermented for 24 or 60 hr. In summary, the different fermentation times of the YCs can markedly improve the growth performance and FCR of broilers by altering the caecal microbial community, and the growth performance which is related to the changes in key metabolic pathways.     

Effects of oxidative stress induced by high dosage of dietary iron ingested on intestinal damage and caecal microbiota in Chinese Yellow broilers

The objective of this trial was to test the effects of oxidative stress induced by a high dosage of dietary iron on intestinal lesion and the microbiological compositions in caecum in Chinese Yellow broilers. A total of 450 1‐day‐old male chicks were randomly allotted into three groups. Supplemental iron (0, 700 and 1,400 mg/kg) was added to the basal diet resulting in three treatments containing 245, 908 and 1,651 mg/kg Fe (measured value) in diet respectively. Each treatment consisted of six replicate pens with 25 birds per pen. Jejunal enterocyte ultrastructure was observed by transmission electron microscopy. The results showed that a high dosage of dietary iron induced oxidative stress in broilers. Dilated endoplasmic reticulum (ER), autophagosome formation of jejunal enterocytes and decreased villi were caused by this oxidative stress. Compared to the control, concentration of the malondialdehyde (MDA) in jejunal mucosa in the 908 and 1,651 mg/kg Fe groups increased by 180% (p < .01) and 155% respectively (p < .01); activity of copper‐zinc superoxide dismutase (Cu/ZnSOD) increased in jejunum (p < .01); and the concentration of plasma reduced glutathione (GSH) decreased by 34.9% (p < .01) in birds fed 1,651 mg/kg Fe. Gene expression of nuclear factor, erythroid‐derived 2‐like 2 (Nrf2) and zonula occludens‐1 (ZO‐1), in the higher dietary Fe groups was enhanced (p < .05). Species of microbial flora in caecum increased caused by oxidative stress. The PCR‐DGGE (denaturing gradient gel electrophoresis) dendrograms revealed different microbiota (65% similarity coefficient) between the control and iron‐supplemented groups (p < .05). These data suggest high dosage of iron supplement in feed diet can induce oxidative stress in Chinese Yellow broilers, and composition of microbiota in the caecum changed. It implied there should be no addition of excess iron when formulating diets in Chinese Yellow broilers.     

Impact of reduced dietary crude protein levels and phytase enzyme supplementation on growth response,slurry characteristics,and gas emissions of growing pigs

This experiment was carried out to evaluate the effect of reduced dietary crude protein (CP) levels supplemented with or without exogenous phytase on growing pigs. Six dietary treatments arranged in a 3 × 2 factorial arrangements of 3 CP levels (containing 14%, 16%, and 18% CP) supplemented each with or without 5,000 FTU/g phytase enzyme. Thirty growing pigs (average weight of 17.80 ± 0.10 kg) were allotted to the six dietary treatments in a complete randomized design. The final weight, daily weight gain, and feed conversion ratio (FCR) increased significantly with increasing CP levels. While, phytase supplementation improved (p = .044) FCR in pigs. Total solid and volatile solid content of the slurry were higher (p = .001) in pigs fed 14% and 16% CP diets supplemented with phytase when compared with other treatment groups. Concentration of methane gas emitted was lowest (p = .001) in the slurry of pigs fed 14% CP diet with or without phytase and those fed 16% CP diet with phytase supplementation. In conclusion, reduction in dietary CP levels resulted in reduced weight gain and poor FCR. While, reduced CP with phytase supplementation reduced concentration of methane gas emitted.     

Effect of protease derived from Pseudoalteromonas arctica supplementation on growth performance,nutrient digestibility,meat quality,noxious gas emission and blood profiles in finishing pigs

This study was conducted to evaluate the effects of dietary supplementation of protease derived from Pseudoalteromonas arctica (PPA) in finishing pigs. A total of 160 pigs were used in this 10‐week trial. Dietary treatment groups were as follows: CON (basal diet); TRT1 (basal diet + 0.1% PPA); TRT2 (basal diet + 0.2% PPA); and TRT3 (basal diet + 0.3% PPA). During weeks 1–5, pigs fed with different levels of PPA‐supplemented diet showed linear increase (p < .05) in the apparent total tract digestibility (ATTD) of nitrogen (N) and linear decrease (p < .05) in the concentrations of serum total protein. During weeks 6–10, pigs fed with different levels of PPA‐supplemented diet showed a linear decrease in feed conversion ratio (p < .05). During the overall period, there was a linear decrease in feed conversion ratio (p < .05) associated with the inclusion of PPA. Pigs fed diets with 0.2% PPA supplementation had lower (p < .05) feed conversion ratio than those fed CON diet during weeks 6–10 and the overall period, and had higher (p < .05) ATTD of N than those fed CON diet during weeks 1–5. Pigs fed diets with PPA supplementation had lower (p < .05) concentrations of serum total protein than those fed CON diet on week 5. In conclusion, dietary supplementation with PPA diet has beneficial effects on growth performance, nutrient digestibility, backfat thickness and the concentrations of serum total protein.     

Impact of restricting feed and probiotic supplementation on growth performance,mortality and carcass traits of meat‐type quails

The objective of this study was to evaluate the effects of quantitative feed restriction, along with dietary supplementation with a probiotic blend (Protexin) as a natural growth promoter, on the performance, water consumption, mortality rate and carcass traits of meat‐type quails. A total of 250 1‐day unsexed quails were randomly allocated to five equal groups in a completely randomized design. The first group (A) fed a basal diet without any restriction (24 hr/day); the second group (B1) fed the basal diet for 20 hr/day; the third group (B2) fed the basal diet enriched with probiotic (0.1 g/kg diet) for 20 hr/day; the fourth group (C1) fed the basal diet for 16 hr/day; and the fifth group (C2) fed the basal diet enriched with probiotic (0.1 g/kg diet) for 16 hr/day. Birds were fed ad‐libitum from 0–14 days of age, and then the feed restriction regimes started from 14 till 28 days of age. Results showed that quails in the control‐group consumed more feed and water than the other treatment groups (p < .01), however their body weights did not differ (p > .05) compared with the other treated groups. The best feed conversion values were achieved in quails supplemented with probiotic blend (B2 and C2) in comparison with the other groups (p < .01). Feeding probiotic had a positive effect on bird health which reduced the mortality rate. Further, mortality rate was significantly reduced (p < .05) by feed restriction, with or without probiotic supplementation. No carcass parameters were significantly affected (p > .05) by treatments. Our results show that quail could be reared under a feed restriction system, for 4–8 hr daily, along with dietary supplementation of probiotic as growth promoter for better growth performance.     

Evaluating two multistrain probiotics on growth performance,intestinal morphology,lipid oxidation and ileal microflora in chickens

An experiment was conducted to investigate the supplementation of two commercially available multistrain probiotics as an alternative to antibiotics on growth performance, intestinal morphology, lipid oxidation and ileal microflora in broiler chickens. A total of 280‐day‐old ROSS 308 mixed‐sex broiler chickens with an average initial body weight of 42 ± 0.5 g were randomly divided into four treatments with five replicate cages of 14 birds each cage in a completely randomized design and fed with the following diets for 42 day: (a) control (CON) (antibiotic‐free diet), (b) antibiotic (ANT) (CON + Avilamycin 150 g/ton feed), (c) probiotic A (CON + Protexin^® 150 g/ton feed) and (d) probiotic B (CON + Bio‐Poul^® 200 g/ton feed). The results showed the broilers fed the ANT diet had greater average daily gain than broilers fed the CON diet during day 1–14 (p < 0.05). At day 42, two birds were randomly selected per replicate for evaluation intestinal morphology, lipid oxidation and ileal microflora. birds fed diet supplemented with probiotic A and probiotic B increased villus height and goblet cells numbers in the jejunum and villus height to crypt depth ratio and villus height in the ileum as compared to birds fed CON diet (p < 0.05). The malondialdehyde value was reduced (p < 0.05) in the ANT, probiotic B and probiotic A groups compared with the CON group. The Lactobacillus population was increased and Clostridium spp. population decreased in the ileum of broilers fed diets containing the probiotic B and probiotic A compared with those fed CON diet (p < 0.05). The results from this study indicate that the probiotic A (Protexin^®) and probiotic B (Bio‐Poul^®) used in this trial may serve as alternatives to ANT.     

Effects of a New Recombinant Phytase on the Performance and Mineral Utilization of Broilers Fed Phosphorus-Deficient Diets

An experiment was conducted with Arbor Acres broiler chickens that were fed 3 experimental diets—a control diet containing an adequate level of available phosphorus (AP) and 2 diets that were deficient in AP but supplemented with phytase at a level of either 500 or 750 phytase units/kg—to assess the effects of a novel microbial phytase supplement in broilers fed AP-deficient diets on growth performance and mineral utilization. Similar average daily gain, feed intake, and feed efficiency (P > 0.05) were obtained among broilers fed different diets. Compared with broilers fed the control diet, broilers fed diets with phytase had greater (P < 0.05) retention of Ca, P, and Zn. Moreover, the levels of Cu, Zn, Mg, and Mn in the tibia bone at 28 d of age, and Zn and Mn at 42 d of age in birds fed diets with phytase exceeded (P < 0.05) those of birds fed the control diet. Supplementation of phytase increased Zn and Mg contents in the plasma at 42 d of age. Birds responded similarly to phytase supplemented at a level of 500 or 750 phytase units/kg in terms of growth performance, mineral retention, and mineral content in the serum and bone. Therefore, with the supplementation of this novel phytase, it is possible to reduce the dietary levels of P and other minerals to below the recommended levels of the Feeding Standard of Chicken in P. R. China (ZB B 43005-86).     

Effects of Source of Inorganic Phosphorus and Phytase Supplementation on Performance, Physiological Parameters and Bone Mineralization in Broilers

The objective of this study was to evaluate the effects of inorganic phosphorus source and phytase addition on performance, nutrient digestibility and bone mineralization in broiler chickens. In Exp. 1, 150 two-day old, male broiler chicks were fed a corn-soybean meal basal diet supplemented with phosphorus provided by dicalcium phosphate, tricalcium phosphate or defluorinated rock phosphate. Five cages containing 10 birds were allotted to each of the three treatments. In Exp. 2, 120 three-day old, male broiler chicks were fed the basal diet from Exp. 1 supplemented with 0, 250, 500, or 1,000 FTU phytase per kg of diet. Six cages containing five chicks were allotted to each of the four treatments. In Exp. 1, there was no difference in weight gain, feed intake or feed conversion as a result of feeding the different sources of inorganic phosphorus. The digestibility of phosphorus was significantly lower (P = 0.01) for chicks fed diets supplemented with tricalcium phosphate than for chicks fed the other two diets.  However, despite the lower digestibility, serum phosphorus levels did not differ among the three treatments. For Exp. 2, feed conversion showed a linear improvement (P = 0.03) with increasing levels of phytase inclusion (days 0 to 33).  Phytase supplementation resulted in linear increases in the digestibility of dry matter (P = 0.02), crude protein (P = 0.04) and energy (P < 0.01).  Chicks fed 1,000 FTU/kg phytase had significantly higher bone calcium (P = 0.05) and bone breaking strength (P = 0.04) than chicks fed the basal diet on day 33. In conclusion, the results of the current study indicated that the performance of birds fed diets supplemented with dicalcium phosphate, tricalcium phosphate or defluorinated phosphate was similar and therefore production costs could be lowered by choosing the cheapest inorganic phosphorus source when formulating diets for poultry. When diets were formulated to meet dietary phosphorus requirements, the growth of broilers was not enhanced with phytase supplementation.  However, increases in feed conversion and bone breaking strength and its potential to impact culling and mortality in broiler operations may be sufficient justification for the routine inclusion of phytase in diets fed to broilers.     

Superdosing phytase reduces real-time gastric pH in broilers and weaned piglets

1. The current study was conducted to investigate the effect of high phytase doses on growth performance and real-time gastric pH measurements in broiler chickens and pigs.

2. In the first experiment, 576 male Ross 308 broilers were fed in two phases (0–21 and 21–42 d) with 4 treatment groups, with diets meeting nutrient requirements containing 0, 500, 1500 or 2500 FTU/kg phytase. In the second, 64 Landrace weaners were fed on diets meeting nutrient requirements with or without phytase (0 or 2500 FTU/kg) in two phases (0–21 and 21–42 d). Heidelberg pH capsules were administered to 7 broilers and approximately 13 pigs per treatment group, pre- and post-phase change, with readings monitored over several hours.

3. Addition of phytase into an adequate Ca and P diet had no significant effect on broiler performance although phytase tended (P < 0.07) to improve feed conversion in pigs over the entire experimental period. Real-time pH capsule readings in broilers demonstrated an increase (P < 0.05) in gizzard pH when phytase was dosed at 500 or 1500 FTU/kg, while higher doses of 2500 FTU/kg phytase lowered pH to a level comparable to control birds. Gastric pH increased (P < 0.01) when animals were exposed to dietary phase change, signifying a potential challenge period for nutrient digestibility. However, pigs fed 2500 FTU/kg were able to maintain gastric pH levels through diet phase change. In contrast, spear-tip probe measurements showed no treatment effect on gastric pH.

4. These findings demonstrate dietary manipulation of gastric pH and the value of real-time pH capsule technology as a means of determining phytase dose response.     

Exogenous protease supplementation of poultry by‐product meal‐based diets for broilers: Effects on growth,carcass characteristics and nutrient digestibility

An experiment was conducted to investigate the effects of three levels (0%, 3% and 6%) of poultry by‐product meal (PBM) with or without protease on broiler growth, carcass characteristics and nutrient digestibility from 1 to 35 days. Two hundred and forty birds (n = 240) were fed equi‐caloric and equi‐nitrogenous (ME 2850 kcal/kg; CP 20%) diets throughout the experiment. The enzyme supplementation increased feed intake (p < .01) and body weight gain (p < .01), but feed:gain remained unaffected (p > .05) from 1 to 21 days. Increasing level of PBM decreased feed intake (p < .05), but body weight gain was improved (p < .05) at 3% PBM level during 1 to 21 days. The feed:gain was improved (p < .05) in birds fed diets containing 3% PBM. The feed:gain was also improved in birds fed diets containing 3% PBM from 1 to 35 days. However, feed intake and body weight gain in birds fed diets containing PBM remained unaffected. An interaction (p < .01) on feed intake between enzyme and PBM was noticed during 1 to 21 days. However, no interaction was recorded for body weight gain and feed:gain. The per cent carcass yield improved (p < .01) in birds fed diets supplemented with enzyme. The per cent breast meat yield was depressed (p < .005) in birds fed diets containing PBM. Apparent metabolizable energy (p < .001), nitrogen retention (p < .01), apparent metabolizable energy corrected for nitrogen (p < .001), and apparent digestibility coefficient for nitrogen (p < .01) improved in birds fed diets containing enzyme; however, a reverse was noticed in those fed diets containing only PBM. In conclusion, inclusion of 3% PBM along with supplementation of exogenous protease improved performance and nutrient digestibility in broilers.     

Effect of L‐theanine on meat quality,muscle amino acid profiles,and antioxidant status of broilers

This study investigated the effect of L ‐theanine on carcass traits, meat quality, muscle antioxidant capacity, and amino acid (AA) profiles of broilers. Three hundred 1‐day‐old Ross 308 male broilers were randomly allotted to five groups with six replicates. Birds were fed the basal diet or basal diet with 300, 600, 900, or 1,500 mg/kg L ‐theanine for 42 consecutive days. The results showed that L ‐theanine quadratically increased dressing percentage, eviscerated percentage, and leg muscle yield (p < .05). Meanwhile, drip loss, cooking loss, shear force, L*_24h, and muscle lactate content decreased quadratically in response to dietary L ‐theanine supplementation (p < .05), while pH_24h and muscle glycogen content were quadratically improved by L ‐theanine (p < .05). Notably, the contents of muscle malondialdehyde and protein carbonyl, and the activities of muscle total antioxidant capacity, catalase, and glutathione peroxidase decreased quadratically in response to dietary L ‐theanine supplementation (p < .05), suggesting that the oxidative stress level of muscle was decreased quadratically. Moreover, L ‐theanine quadratically increased the concentrations of most of muscle essential AA, nonessential AA, and flavor AA (p < .05). In conclusion, L ‐theanine can be used as a valuable feed additive to modulate carcass traits, meat quality, muscle antioxidant status, and AA profiles of boilers, and its optimum addition level is 600 mg/kg based on the present study.     

Effects of adding high-dosing Aspergillus oryzae phytase to corn–wheat–soybean meal-based basal diet on growth performance,nutrient digestibility,faecal gas emission,carcass traits and meat quality in growing-finishing pigs

This study tests the effects of supplementation of high-dosing Aspergillus oryzae phytase into the corn – wheat – soybean meal (SBM)-based basal diet on growth performance, nutrient digestibility, faecal gas emission, carcass traits and meat quality in growing-finishing pigs (29.73–110.86 kg live weight; 70-day-old to 166-day-old). A total of 56 crossbred pigs [(Landrace × Yorkshire) × Duroc] were divided into two dietary groups for a 96-day experiment (growing period, days 0 – 42; finishing period, days 43 – 96) with a completely randomized block design. There were seven replicate pens in each dietary group, and each pen has four pigs (two barrows and two gilts). The dietary treatments consisted of a corn – wheat – SBM-based nutrient sufficient basal diet or the basal diet supplemented with 1500 FTU/kg A. oryzae phytase. One phytase unit (FTU) was defined as the amount of enzyme that catalyses the release of one micromole phosphate from phytate/min at 37°C and pH 5.5. Higher average daily gain and lower feed conversion ratio were observed in growing-finishing pigs consuming a high-dosing A. oryzae phytase supplementing diet during days 0 – 42 and 0 – 96. Supplementing high-dosing A. oryzae phytase to the diet of growing-finishing pigs increased apparent total tract digestibility of phosphorus on days 42 and 96. Moreover, growing-finishing pigs fed the diet supplemented with high-dosing A. oryzae phytase had higher carcass back-fat thickness than those fed the control diet. However, the faecal gas emission and meat quality were not affected by high-dosing A. oryzae phytase supplementation. In conclusion, dietary supplementation of high-dosing A. oryzae phytase (1500 FTU/kg) had beneficial effects on the growth performance, apparent phosphorus digestibility and carcass back-fat thickness in growing-finishing pigs.     

Effect of resveratrol on growth performance,rectal temperature and serum parameters of yellow‐feather broilers under heat stress

This study investigated the effect of dietary resveratrol supplementation on growth performance, rectal temperature, and serum parameters of yellow‐feather broilers under heat stress. A total of 480 yellow‐feather broilers (28‐day‐old) were randomly allotted to five groups with six replicates. A thermoneutral group (TN) (24 ± 2°C) received a basal diet and another four heat‐stressed groups (37 ± 2°C for 8 hr/day and 24 ± 2°C for the remaining time) were fed the basal diet or basal diet with 200, 350, and 500 mg/kg resveratrol for 14 consecutive days. The results revealed that resveratrol supplementation improved average daily gain (p = 0.001), and decreased (p < 0.05) rectal temperature from d 3 when compared with heat‐stressed group without resveratrol. In addition, supplementation with resveratrol at 350 or 500 mg/kg lowered (p < 0.05) the contents of corticosterone, adrenocorticotropic hormone, cholesterol, triglycerides, uric acid, malonaldehyde, and activities of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase, increased (p < 0.05) the levels of triiodothyronine, the ratio of triiodothyronine to thyroxine, total protein, glutathione, and activities of alkaline phosphatase, total superoxide dismutase, catalase, and glutathione peroxidase, though with few fluctuation. In conclusion, supplementation with resveratrol can improve the growth performance by positively regulating serum metabolic parameters and alleviating tissue oxidant damage of broilers under heat stress.     

Effects of Astragalus membranaceus,Codonopsis pilosula and allicin mixture on growth performance,nutrient digestibility,faecal microbial shedding,immune response and meat quality in finishing pigs

A 12‐week trial with 120 [(Landrace×Yorkshire)×Duroc] pigs (45.65 ± 1.93 kg) was conducted to evaluate the effects of Astragalus membranaceus, Codonopsis pilosula and allicin mixture (HM) supplementation on growth performance, nutrient digestibility, faecal microbial shedding, immune response and meat quality in finishing pigs. Pigs were allocated to one of three treatments with 0, 0.025% (HM1) and 0.05% (HM2) HM supplementation in a randomized complete block design according to sex and BW. Each treatment contained 10 replications with four pigs (two barrows and two gilts) per pen. Dietary HM resulted in a higher G:F (p < 0.05) than CON group during weeks 7 to 12 and the overall periods. Pigs fed HM2 diet had higher ADG than pigs fed CON diet. Pigs fed HM2 supplementation diet led to a higher (p < 0.05) apparent total tract digestibility (ATTD) of dry matter (DM) and gross energy (GE) than pigs fed CON diet at week 6, while the supplementation of HM led to a higher (p < 0.05) ATTD of DM and GE than pigs fed CON diet at week 12. The faecal E. coli counts were reduced, and Lactobacillus counts were increased by increasing HM supplementation (p < 0.05). Pigs fed HM1 diet had higher (p < 0.05) WBC concentration than those fed CON and HM2 diets at week 6. Pigs fed HM‐supplemented diet had higher (p < 0.05) IgG and IgA concentrations than those fed CON diet at week 12. Pigs fed HM diet noted better (p < 0.05) meat colour and redness value than pigs fed CON diet. Pig fed HM2 reduced (p < 0.05) the lightness value compared with CON group. In conclusion, dietary HM supplementation exerted beneficial effects on growth performance, nutrient digestibility, intestinal microbial balance (increased Lactobacillus counts and decreased E. coli counts), immune response and meat quality.