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.

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Feed is a main challenge for a livestock farm, especially during dry season when feed production is low. Such condition may cause low livestock productivity due to insufficient nutrient intake. Provision of high quality forages from grasses and legumes are limited by land competition for various developmental reasons. Therefore, an opportunity to provide feed for livestock is through utilization of agroindustrial by-products such as soy sauce by-product. The objective of the present study was to evaluate soy sauce by-product on addition of tannins, i.e., Acacia mangium Wild. (AT) and chestnut tannin (CT) using an in vitro rumen fermentation technique. The following treatments were tested: soy sauce by-product as control (R1), soy sauce by-product + 1% AT (R2), soy sauce by-product + 2% AT (R3), soy sauce by-product + 1% CT (R4) and soy sauce by-product + 2% CT (R5). The treatments were incubated in vitro with buffered-rumen fluid in four replicates, represented by three incubation units per replicate, and conducted for 24 h at 39 °C. Parameters measured in this research were in vitro gas production at regular time point intervals. Other parameters measured after the incubation were dry matter degradation, organic matter degradation, total volatile fatty acids (VFA), ammonia (NH3) and pH. Data were tested using analysis of variance (ANOVA), if there was a significant different at P<0.05 then continued with Duncan’s multiple range test. The results of this study showed that the addition of tannins, both acacia and chestnuts, had no significant effect (p>0.05) to dry matter degradation, organic matter degradation, total volatile fatty acids (tVFA), NH3 and pH. Acacia tannin was able to influence (p<0.05) the accumulation of gas production at 8, 12 and 24 h. It can be concluded that the addition of tannin, both acacia and chestnuts up to level 2% does not interfere with the fermentation process of soy sauce by-product in the rumen an in vitro.

A 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 Systematic Review for Laboratory Animal Experimentation (SYRCLE'). The final dataset consisted of 21 in vivo studies covering 83 treatment units. Meta-analysis was performed using a non-linear mixed model (NLME) library. The quadratic patterns (P < 0.001) of the gain:feed ratios were calculated based on the result of meta-analyses of goose data. The linear patterns (P < 0.001) of foie gras quality were also presented. It was concluded from the meta-analysis based on in vivo studies that fibre-rich ingredients effectively improved foie gras quality.

Tannin is one of plant secondary metabolites that could protect proteins from various microbes, both in feed material and in the rumen. Tannin can be used as an additive in the silage production process, especially high-protein feed material. The study aimed to evaluate the physical quality of soy sauce by-product silage treated with Acacia mangium Wild. tannin (AT; condensed tannin). This study used the fresh soy sauce by-product, tannin of acacia and chestnut (CT; hydrolysable tannin), BAL and propionate acid (PA). Soy sauce by-product was fermented in silo with a capacity of 1.3 Kg. This experiment was arranged in a complete randomized design with 6 treatments and 3 replications. The treatments were (R1) fermented soy sauce by-product, (R2) R1+4.5 mL BAL 106, (R3) R1+2% AT, (R4) R1+2% CT, (R5) R1+0.5% PA and (R6) R1+combination of 1% AT, 1% CT and 0.5% PA. The observed variables were the loss of dry matter (%), temperature (⁰ C), smell, color and emerged fungus on silage. Analysis of variance was performed by SPSS version 23. For any significant difference between treatments was evaluated by Duncan's Multiple Range Test (DMRT) at the level of confident 5%. The result showed that AT suppressed the loss of dry matter up to 0.91%, and produced no smell with black color such as soybean color. The silage temperature was relatively similar for about 28.9-29.4ºC, no emerged fungus, and did not able to maintain the normal silage temperature. Nevertheless, the use of acacia and chestnut tannin could produce a good quality soy sauce by-product silage.

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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.

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.