The objective of the present study was to develop linear and non-linear statistical models for prediction of enteric methane emission (EME) in sheep. A database from 80 publications, which included a total of 449 mean observations of EME measured on more than 1500 sheep, was constructed to develop prediction and evaluation of models of EME. Dietary nutrient composition (g/kg), nutrient or energy intake (kg/day or MJ/day) and digestibility (g/kg) of organic matter were used as predictors of EME (MJ/day). The dietary concentrations of neutral detergent fibre and crude protein, and feed intake, were 435 g/kg, 152 g/kg and 0.92 kg/day, respectively. The EME by sheep expressed as MJ/day and % of gross energy intake was 1.02 and 6.54, respectively. The simple linear equation that predicted EME with high precision and accuracy was EME = 0.208(±0.040) + 0.049(±0.0039) × gross energy intake (MJ/day), adjusted R2 = 0.86 with root mean-square prediction error of 22.7%, of which 93% was from random error and regression bias of 3.20%. Additions of dietary concentration of fibre and feeding level, and organic matter digestibility to the simple linear model improved the models. Among the non-linear equations developed, monomolecular model, i.e. EME = 5.699 (±1.94) – [5.699 (±1.94) – 0.133 (±0.047)] × exp[–0.021(±0.0071) × metabolisable energy intake (MJ/day)]; adjusted R2 = 0.90 and mean-square prediction error = 20.1%, with 96.3% random error, performed better than simple linear and other non-linear models. The equations developed in the present study will be useful for national methane inventory preparation, and for a better understanding of dietary factors influencing EME in sheep.

Three hundred thirty‐day‐old unsexed commercial broiler chicks (Vencobb‐400) with initial average body weight of 44.04 ± 0.42 g were allocated into five experimental groups, in a completely randomized design (CRD) with 21‐day experiment. Groups were formed according to dose of supplemental L‐threonine in various rations i.e., 100% NRC specification, 100% threonine of Vencobb‐400 strain specification, 110% threonine of Vencobb‐400 strain specification, 120% of threonine of Vencobb‐400 strain specification and 130% threonine of Vencobb‐400 strain specification. Average daily feed intake (ADFI), average daily body weight gain (ADG), cumulative feed conversion ratio (CFCR), carcass characteristics, immune response, intestinal morphometry and biochemical profile were studied. The ADFI and ADG increased linearly and quadratically as dietary threonine levels were increased. However, the CFCR did not differ (p ˃ 0.05) among the groups. Though the carcass weight and drumstick yield did not differ (p ˃ 0.05) among the groups, the relative breast yield increased linearly (p = 0.007). The relative dressing yield and relative thigh weight increased linearly (p = 0.05 and p = 0.03, respectively). The relative weight of immune organs like bursa and thymus increased linearly. The mean total serum immunoglobulin, ND‐ELISA titre and the mean lymphocyte proliferation response index increased linearly, whereas mean phagocytic activity index of neutrophil increased linearly (p < 0.001) and quadratically (p = 0.001). The mean villus height (VH), crypt depth (CD), villus surface area and mean goblet cell number/villus increased linearly and quadratically, whereas the villus width (VW) and goblet cell density increased quadratically. The serum glucose increased linearly (p = 0.001), whereas serum total protein concentration and serum globulin level increased both linearly and quadratically. The albumin: globulin ratio tended to decrease linearly. There was a significant decrease (p < 0.05) in serum cholesterol and VLDL cholesterol level. However, a linear increment (p = 0.04) in the blood serum HDL cholesterol level with a linear reduction (p = 0.01) in the blood serum LDL cholesterol was noticed.

A study was conducted to investigate the dietary supplementation of black cumin seeds (BCS) on carcass characteristics, chemical and fatty acid (FA) composition and antioxidant properties of thigh and breast meat of broiler chickens at 42 days of age. Three hundred sixty 1-day-old broiler chickens were allocated to five dietary treatment groups (each group containing eight replicate pens with each pen containing nine broiler chickens): basal diet (control; CON), CON + 0.05 g/kg of bacitracin methylene disalicylate (AB), CON + 5 g/kg of BCS (low dose of BCS), CON + 10 g/kg of BCS (medium dose of BCS) and CON + 20 g/kg of BCS (high dose of BCS). Weight (g) of slaughtered birds (p = .03), hot carcass (p = .007), breast (p = .03), thigh (p < .001), wing (p = .06), neck (p = .01), liver (p = .09), abdominal fat (p = .01) and total edible parts (p = .01) increased or tended to increase due to BCS supplementation compared with the CON. The concentrations of dry matter, crude protein and ether extract in chicken thigh and breast meat increased (p = .038 to <.001) with increasing doses of BCS in diets. The ferric reducing antioxidant activity in blood and meat increased linearly with increasing doses of BCS in the diets. However, peroxide values in meat were not affected by BCS and AB on both days 1 and 7 of storage at 4°C. Supplementation of BCS increased the concentrations of C14:1, C18:3n-6, C20:1, C20:2 FA and PUFA linearly (p < .05) and tended to increase (p = .098) the concentration of C18:2cis linearly. However, the concentrations of C16:0 and C16:1 FA decreased linearly with increasing doses of BCS in the diets. In conclusion, dietary supplementation of BCS at 20 g/kg diet may improve slaughter body weight, beneficial FA concentrations and antioxidant properties of broiler chicken meat.

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Threonine is one of the important limiting amino acids (after methionine and lysine) in broiler diets. Adequate threonine level is mandatory to obtain optimal growth of broilers. Threonine takes part in some important metabolic processes (uric acid formation and protein synthesis). It represents 30% of the total amino acid content of mucin. Threonine plays an immense role in gastrointestinal health and thus threonine optimization may protect the intestine from microbial infections. It is presumed that threonine level of healthy diet is not sufficient when the animal experiences a gut challenge either by microbial invasion and/or added with environmental extremes. Till date no guideline has been framed for optimizing the requirement of threonine considering the role of mucin in gut health of poultry. Hence, optimizing the supplemental threonine level in commercial broiler chicken for better performance and gut fitness is utmost necessary.

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