Guiqin Yang

Objective: This study was conducted to investigate the effects of rumen-protected biotin (RPB) on growth performance, nutrient digestibility, nitrogen utilization and plasma biochemical parameters of Liaoning cashmere goats during the cashmere fiber growing period.Methods: Sixteen 6-month-old Liaoning cashmere twin-doelings (24.8±1.20 kg) were allocated to 2 diet groups that were individually ad libitum fed 30% concentrate and 70% forage diet (dry matter [DM]) by a paired experimental design. Goats of the control group were fed the basal diet, while goats belonging to the RPB group were fed the basal diet with 10 mg RPB/d per animal. The duration of the experiment was 16 weeks with two 8-week periods. Digestibility was determined at weeks 7 and 15, and other measures were taken every four weeks.Results: Compared with the control group, the average daily gain of the RPB group increased by 10.94% (p<0.05), and the intake of neutral detergent fiber was increased (p = 0.045). There were some increasing tendencies for the intake of DM, acid detergent fiber and ether extract (p = 0.070, 0.088, and 0.070, respectively). The intake and digestibility of N tended to increase (p = 0.062 and 0.093, respectively), while the N fecal excretion percentage of N intake was decreased (p = 0.093) in the RPB compared with the control group. N retention tended to increase (p = 0.084) with the addition of adding RPB to the diet. Plasma total protein was increased (p = 0.037), whereas the urea-N concentration was decreased (p = 0.049) in the RPB diet group compared with the control diet group. The levels of propionyl-CoA carboxylase (p<0.001) and methylmalonyl-CoA (p = 0.013) were increased in the RPB group.Conclusion: Supplementation of rumen-protected biotin in the diet of cashmere goats can enhance the utilization of N and improve daily weight gain during cashmere fiber growing period.

Objective: The objective of this study was to investigate the effect of supplementation with enzymolytic soybean meal (ESBM) on broilers fed low crude protein (CP) diets.Methods: A total of 360 one-day-old broilers were randomly assigned to six treatments with 6 replicates per treatment and 10 chicks per replicate for a period of 42 days. Chicks were fed a basal standard high-CP diet as a positive control (PC), a low-CP diet (reducing 10 g/kg CP from the PC) as a negative control (NC), or an NC + 0.5%, 1.0%, 1.5%, or 2.0% ESBM diet.Results: Compared to chicks fed the PC, chicks fed the NC had a decreased body weight gain (BWG, p<0.05) from 1 to 42 days, but supplementation with 2.0% ESBM restored BWG (p<0.05) and even linearly improved the feed conversion rate (FCR, p<0.05). Digestibility of CP and ether extract was increased (p<0.05) in chicks fed a 1.0% ESBM diet compared to the PC. With increasing levels of ESBM, nitrogen (N) excretion decreased (p0.05) serum concentrations of total protein, albumin and total cholesterol but led to a descending trend in triglycerides and an ascending trend in calcium and urea N at 42 days (p0.05) in villus height (VH), crypt depth (CD), and VH/CD (V/C) of the duodenum and jejunum between the PC and NC at both 21 days and 42 days, while increasing dietary ESBM levels linearly (p<0.05) decreased CD and increased V/C of the duodenum and jejunum at both 21 days and 42 days.Conclusion: The findings indicated that ESBM could be used in broiler low-CP diets to improve production performance, decrease N excretion, and enhance intestinal health.

Background: Public complaints concerning odor emissions from intensive livestock and poultry farms continue to grow, as nauseous odorous compounds have adverse impacts on the environment and human health. Itaconic acid is a metabolite from the citric acid cycle of the host and shows volatile odor-reducing effects during animal production operations. However, the specific role of itaconic acid in decreasing intestinal odorous compound production remains unclear. A total of 360 one-day-old chicks were randomly divided into 6 treatment groups: control group (basal diet) and itaconic acid groups (basal diet + 2, 4, 6, 8 and 10 g/kg itaconic acid). The feeding experiment lasted for 42 d. Results: Dietary itaconic acid supplementation linearly and quadratically decreased (P < 0.05) the cecal concentrations of indole and skatole but did not affect (P > 0.05) those of lactic, acetic, propionic and butyric acids. The cecal microbial shift was significant in response to 6 g/kg itaconic acid supplementation, in that the abundances of Firmicutes, Ruminococcus and Clostridium were increased (P < 0.05), while those of Bacteroidetes, Escherichia-Shigella and Bacteroides were decreased (P < 0.05), indicative of increased microbial richness and diversity. Furthermore, a total of 35 significantly (P < 0.05) modified metabolites were obtained by metabolomic analysis. Itaconic acid decreased (P < 0.05) the levels of nicotinic acid, nicotinamide, glucose-6-phosphate, fumatic acid and malic acid and increased (P < 0.05) 5-methoxytroptomine, dodecanoic acid and stearic acid, which are connected with the glycolytic pathway, citrate acid cycle and tryptophan metabolism. Correlation analysis indicated significant correlations between the altered cecal microbiota and metabolites; Firmicutes, Ruminococcus and Clostridium were shown to be negatively correlated with indole and skatole production, while Bacteroidetes, Escherichia-Shigella and Bacteroides were positively correlated with indole and skatole production. Conclusions: Itaconic acid decreased cecal indole and skatole levels and altered the microbiome and metabolome in favor of odorous compound reduction. These findings provide new insight into the role of itaconic acid and expand its application potential in broilers.

Objective: This study was conducted to evaluate the interactive effects of dietary digestible tryptophan (dTry) and soy oligosaccharides (SO) on growth performance, caecal skatole level, and microflora of broiler chickens aged from 14 to 42 days.Methods: Three hundred and sixty broiler chicks were allocated equally to 36 cages at 14-dayof- age according to body weight and gender. Using a 3×2 factorial arrangement, 3 dietary dTry levels (0.18%, 0.23%, and 0.28%) supplemented with 0 or 3.5 g/kg of SO were used to create 6 diets (treatments). Each diet was fed to six replicates of 10 birds (60 birds/treatment), growth performance was measured. Caecal content samples were collected at 42 days of age.Results: Results showed that significantly different dTry level×SO interactions were found for average daily gain (ADG), caecal levels of indole, propionic acid, and butyric acid, and microbial Shannon index (p<0.05). Birds fed diet containing 0.23% dTry level with SO supplementation had higher ADG and lower feed/gain ratio than those fed the other diets (p<0.05). Broilers fed diets containing 0.28% dTry increased their caecal levels of indole and skatole compared with those containing 0.18% or 0.23% dTry (p<0.01), regardless of SO addition. SO supplementation to diets decreased the caecal skatole level by 16.17% (p<0.05), and increased the relative frequency of Clostridium IV (p<0.05), regardless of dietary dTry level.Conclusion: These results indicated that diets containing 0.23% dTry with SO supplementation positively promoted ADG, and decreased caecal skatole levels of broiler chickens. The dietary dTry level, SO affected the caecal skatole level, however, there was no interaction between them.

Objective: The objective of this study was to investigate the in vitro fermentation profiles of different soybean oligosaccharides (SBOs) and their effects on skatole production and cecal microbiota of broilers.Methods: Five SBOs with varying main component contents were fermented using an in vitro batch incubation inoculated with broiler cecal microbiota. Gas production was recorded automatically, skatole, indole and short-chain fatty acids (SCFAs) were determined using high-performance liquid chromatography, and microbial changes were analyzed using 16S DNA gene sequencing.Results: The addition of SBOs increased (p<0.05) gas production, suggesting bacterial growth-stimulating activities. In addition, the concentrations of indole were significantly (p<0.05) decreased after SBO supplementation, and SBO III, with higher sucrose and stachyose contents, decreased (p<0.05) the skatole level. Our results also revealed that the fermentation of SBOs by cecal microbiota produced (p<0.05) SCFAs, which were dominated by propionic acid, butyrate acid and lactic acid compared to the control. In addition, SBO III increased (p<0.05) the abundance of Firmicutes and Subdoligranulum and decreased that of Bacteroides.Conclusion: These results suggest that SBOs with higher sucrose and stachyose contents are promising prebiotics in modulating gut microbiota and reducing odor emission in broilers.

Objective: To investigate the effects of enzyme-bacteria co-fermented feed on broilers, the basal diet (BF) was pretreated by microbial enzyme co-fermentation, and then different proportions of BF were replaced to study its effects on growth performance, nutrient metabolism and cecal microflora of broilers.Methods: Four hundred and eighty 1-day-old broilers were randomly divided into 6 groups. The control group was fed with BF, and groups 1 to 4 were treated with dried fermented feed (DFF) instead of 10%, 15%, 20%, and 25% the BF, and group 5 was treated with wet fermented feed (WFF) instead of 10% the BF, named BF, 10% DFF, 15% DFF, 20% DFF, 25% DFF, and 10% WFF, respectively. The trial period was 42 days.Results: The results showed that the average daily feed intake and average daily gain of 10% DFF, 15% DFF, and 10% WFF groups were significantly higher than those of the control group at 22 to 42 days and 1 to 42 days (p0.05). At the same time, the nutrient apparent metabolic rate and cecal microbial abundance of each treatment group had an increasing trend (p>0.05).Conclusion: In conclusion, the feed fermented by enzyme and bacteria had a potential promoting effect on the growth performance and nutrient digestibility of broilers.

This study evaluated the effects of starch sources on pellet‐processing characteristics as well as the growth performance and caecal microflora of rabbits. Ninety‐six 35‐day‐old rabbits were randomly allocated to four groups with 24 rabbits per group and were fed diets with different starch sources (corn, wheat, potato or pea starch). The trial lasted for 40 days. The greatest hardness and lowest powder ratio of feed pellets was associated with the use of potato starch (p > 0.05). Pellet bulk density was the highest with corn starch, and the density was greater than that of pea starch by 5.91% (p < 0.05). The pulverisation ratio of corn starch pellets was the lowest, 43.67% lower than that of the pea starch pellets (p < 0.05). The average daily gain of rabbits in the corn starch group was higher than in the potato and pea starch groups, by 7.89% and 10.81%, respectively (p < 0.05). Rabbits in the corn starch group had the best feed conversion ratio (p > 0.05). The feed intake of rabbits in the potato starch group was higher than in the wheat and pea starch groups, by 4.30% and 5.16% respectively (p < 0.05). The dominant caecal bacteria phyla were Firmicutes, Bacteroidetes, Verrucomicrobia and Proteobacteria. There were 12 bacterial genera with proportions greater than 0.1%. The caecal proportion of Clostridium in the pea starch group was 1.8%, which was higher than those of the other groups (p = 0.057). There was no significant difference in caecal microbial diversity among groups (p > 0.05). The highest microbial clustering effect was found in the corn starch treatment. In conclusion, the best pellet quality was found using potato starch; for rabbit growth, the optimal source was corn starch.