Effect of supplementing Leucaena leucocephala leaves alone or in conjunction with malic acid on nutrient utilization, performance traits, and enteric methane emission in crossbred calves under tropical conditions.

Dietary strategies aiming at minimizing enteric methane (CH4) emission in ruminants are of practical interest from nutritional, economical, and environmental point of view. The present study evaluated the effects of supplementing Leucaena leucocephala leaves either alone or in conjunction with malic acid on nutrient utilization, growth performance, and enteric CH4 emission in crossbred cattle fed wheat straw and concentrate-based diet under tropical conditions. Eighteen crossbred (Karan-Fries) calves were randomly allocated into 3 groups: G-I (control)-fed wheat (Triticum aestivum) straw and concentrate mixture in the ratio 50:50; G-II-fed wheat straw, concentrate mixture, and Leucaena leucocephala leaves in the ratio 45:45:10; and (3) G-III-fed similar diet like G-II with an additional supplementation of 1% malic acid on dry matter intake basis. Experimental feeding spanning 90 days included a 7-day metabolism trial and CH4 quantification study by sulfur hexafluoride tracer technique. Results revealed no significant effect of dietary treatments on dry matter intake (DMI) and digestibility of nutrients, except neutral detergent fiber (NDF) digestibility which was 5.5% higher (P < 0.05) in G-III as compared to control. Further, nitrogen (N) metabolism, rumen microbial protein synthesis, and growth performance remained similar among the treatments. No significant effect was also observed for enteric CH4 emission (expressed as g/day and g/kg DMI) in calves supplemented with Leucaena leucocephala leaves and malic acid. Therefore, the present findings depict modest improvement in fiber digestibility with no encouraging effect in mitigating enteric CH4 in growing cattle calves by supplementing Leucaena leucocephala leaves alone or with malic acid within the selected levels.

Perspectives for rare earth elements as feed additive in livestock - A review.

There is a need for newer feed additives due to legal prohibition on inclusion of growth promoting antibiotics in livestock diets in several countries due to antimicrobial resistance. In this context, rare earth elements (REE) have gained attention among animal nutritionists as potential growth promoters. Currently, several studies have reported better weight gain, milk production, egg laying capacity and feed conversion efficiency among different breeds of farm animals following supplementation with REE, with however largely inconsistent results. Furthermore, REE supplementation has also shown to improve ruminal fibrolytic and proteolytic activities as well as flavor of meat with negligible residues in edible tissue, however the mechanism behind this action is still unclear. According to existing research, due to their poor absorption and similarity with calcium REE might exert their action locally on gut microbial populations within the gastrointestinal tract (GIT). Moreover, REE have also shown anti-inflammatory, anti-oxidative as well as immune stimulating effects. The present review aims to broaden the knowledge about use of REE as feed additives for livestock and sum up efficacy of REE supplementation on performance and health of animals by comparing the findings. Till date, researches with REE have shown properties that make them a promising, new and safe alternative feed additive but further exploration is recommended to optimize effects and clarify discrepancy of various results before practical proposals can be drafted.

Effect of Aloe vera and clove powder supplementation on carcass characteristics, composition and serum enzymes of Japanese quails.

AIM: The aim was to study the effect of Aloe vera and clove powder supplementation on carcass characteristics, composition and serum enzymes of Japanese quails. MATERIALS AND METHODS: The study was conducted on 120-day-old Japanese quails, which were randomly divided into four treatment groups viz. T1-control, T2-0.5% A. vera, T3-0.5% clove, and T4-(0.25% A. vera + 0.25% clove) powder, each having three replications consisting of ten Japanese quails. The birds in control group (T1) were fed no supplement whereas in treatments T2-T4 birds were supplemented with A. vera leaf powder, clove, and mixture of both (powdered form) at 0.5, 0.5, and 0.25+0.25% of feed, respectively. After 7 days of brooding, a feeding trial of 35 days was conducted. On 35(th) day of trial birds were sacrificed and dressing percentage, cut up parts, organ weight, processing losses and carcass meat composition of the breast, thigh, and drumstick were recorded. Blood samples were collected on the same day and serum was separated to evaluate serum enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST). RESULTS: It showed significantly (p<0.05) higher values of dressing percentage with and without giblet and breast weight in the T2-T4 group as compared to the T1 group. No significant (p>0.05) differences were observed in giblet weight, other cut up parts and composition of the breast, thigh, and drumstick muscles in all the treatment groups. Serum ALT and AST did not vary significantly among different treatment groups. CONCLUSION: A. vera and clove supplementation improved the dressing percentage and breast weight without adversely affecting the meat composition and serum enzymes. Thus, these can be used as a growth promoter in Japanese quails.