Background and Aim: Tannins are functional secondary metabolites that may provide benefits to ruminants. However, to date, their effects on broiler chickens remain inconclusive. This study aimed to evaluate the effectiveness of dietary tannin levels on the performance, body organs, and amino acid (AA) digestibility of broiler chickens using a meta-analysis. Materials and Methods: After verification and evaluation, a total of 22 articles were included in the present study. All data regarding dietary tannin dosages, performance, digestibility, and gastrointestinal physiology of broiler chickens were tabulated into a database. The database data were then statistically analyzed using mixed models, with tannin dose as a fixed effect and study as a random effect. Results: High levels of dietary tannins negatively affected the average daily gain and average daily feed intake of broiler chickens according to linear patterns (p<0.001). In addition, dietary tannins decreased drumstick and liver weights, as well as bursa of Fabricius and spleen weight (p<0.05). Meanwhile, other carcass traits (i.e., thigh, wings, and body fat) were not influenced by dietary tannins. Regarding AA digestibility, high dietary tannin concentrations induced negative responses on isoleucine, leucine, and methionine digestibility (p<0.05). Conclusion: Dietary tannins appear to have a negative effect on broiler performance, lymphoid organ weight, and AA ileal digestibility. Hence, the addition of tannins to broiler diets is not recommended.

Background and Aim: As a non-protein nitrogen source, urea is a popular, low cost, and easily obtained protein supplement. The objective of the present study was to perform a meta-analysis of the effects of urea supplementation on rumen fermentation and sheep performance. Materials and Methods: A total of 32 experiments from 21 articles were compiled into a dataset. The levels of dietary urea varied from 0 to 31 g/kg of dry matter (DM). Parameters observed were rumen fermentation product, nutrient intake, nutrient digestibility, and sheep performance. This dataset was analyzed using a mixed model methodology, with urea supplementation levels as fixed effects and the different experiments as random effects. Results: Increasing levels of urea were associated with increases (p=0.008) in rumen pH, butyrate (C4) production, and ammonia (NH3–N) concentration. Urea supplementation had minor effects on total volatile fatty acids (p=0.242), total protozoa (p=0.429), and the microbial N supply (p=0.619), but tended to increase methane production (CH4; p<0.001). Supplementation of urea increased the intake of dry matter (DM; p=0.004) and crude protein (CP; p=0.001). Digestibility parameters, such as DM digestibility (DMD) and CP digestibility (CPD), also increased (p<0.01) as a result of urea supplementation. Retained N (p=0.042) and N intake (p<0.001) were higher with increasing levels of urea supplementation. In terms of animal performance, supplementation of urea increased average daily gain (ADG; p=0.024), but decreased the hot carcass weight percentage (p=0.017). Conclusion: This meta-analysis reports the positive effects of urea supplementation on rumen fermentation products (i.e., pH, C4, and NH3–N), intake (DM, CP, and N), digestibility (DMD and CPD), and ADG in sheep.

Meta-analysis was performed to investigate the effect of different sources and levels of dietary fibre-rich ingredients on the growth performance, foie gras quality, and its fatty acid profile in geese. Peer-reviewed articles were strictly evaluated, and selected according to the protocols of the...

The present meta-analysis evaluated the effect of the level of antimicrobial peptides (AMPs) on broiler chicken growth performance, digestibility, small intestine morphology and blood serum parameters. The database was developed from 29 articles comprising 36 experiments. Data were analyzed using...

Aim: The present experiment aimed to evaluate the use of different additives, i.e., lactic acid bacteria (LAB) inoculant, tannin extract, and propionic acid, on the chemical composition, fermentative characteristics, and in vitro ruminal fermentation of soy sauce by-product (SSB) silage. Materials and Methods: SSB was subjected to seven silage additive treatments: Fresh SSB, ensiled SSB, ensiled SSB+LAB, ensiled SSB+2% acacia tannin, ensiled SSB+2% chestnut tannin, ensiled SSB+0.5% propionic acid, and ensiled SSB+1% acacia tannin+1% chestnut tannin+0.5% propionic acid. Ensiling was performed for 30 days in three replicates, and each replicate was made in duplicate. The samples were evaluated for their chemical composition and silage fermentation characteristics and were tested in an in vitro rumen fermentation system. Results: In general, the nutrient compositions did not differ among the tested SSBs in response to the different additives used. The addition of tannins, either acacia or chestnut, and propionic acid significantly decreased the pH of the ensiled SSB (p<0.05). The addition of several additives (except LAB) decreased the ammonia concentration in SSB silage (p<0.05). The total volatile fatty acids in the in vitro rumen fermentation profile of the ensiled SSB were not significantly altered by the various additives applied. The addition of some additives, i.e., ensiled SSB+LAB and ensiled SSB+2% acacia tannin, reduced the digestibility values of the SSB (p<0.05). Different silage additives did not significantly affect methane production, although the addition of acacia tannins tended to result in the lowest methane production among treatments. Conclusion: The use of additives, particularly 2% acacia tannins, can reduce proteolysis in SSB silage.

This study aimed to examine the molasses addition as a glucose source in the process of elephant grass silage. A completely randomized design consisting of five treatments and five replications was used in this study. The treatments were P1: elephant grass (EG) as control, P2: EG + 2.5% molasses, P3: EG + 5% molasses, P4: EG + 7.5% molasses and P5: EG + 10% molasses based on dry matter. All the treatments were ensiled for 30 days. The parameters included physical quality were aroma, mold growth, texture while the chemical quality parameters were pH, dry matter, dry matter loss, and fleigh value. The data were analyzed for variance and if there were differences between treatments, the Duncan's test was conducted at the 5% level. The results showed that 10% molasses addition had a significant effect (p<0.05) on the physical and chemical qualities of elephant grass silage. The elephant grass silage had a distinctive fermented aroma, no fungi, smooth texture, no clump, and brownish-green color following the molasses color. The pH of elephant grass silage was 3.37-4.52, the silage dry matter was around 27.5%-32.5%, the dry matter loss was around 2.76%-6.73%, while the fleigh value was around 79.2-135. It could be concluded that molasses could be used as a stimulant additive to ensilage elephant grass.