Effect of age and different doses of dietary vitamin E on breast meat qualitative characteristics of finishing broilers.

The supplementation of vitamin E on broiler chicken diets is essential to the prevention of lipid oxidation reactions in the meat and improvement of meat quality. The objective of this study was to assess the effect of different doses of dietary vitamin E on breast meat quality of broiler chickens in the finishing period. Five doses of vitamin E were used (30, 90, 150, 210, and 270 mg/kg feed) in broilers' diets from 42 to 54 d of age. A completely randomized design was conducted, followed by a split-plot, where the vitamin E dose was considered as the whole plot, and broilers' age at slaughter was the subplot. Breast meat quality was assessed at 4 different ages (45, 48, 51, and 54 d old), using 50 birds per age, totaling 200 birds. Meat quality characteristics evaluated were: pH at 24 h post mortem, color (brightness, redness, and yellowness), water holding capacity, cooking loss, shear force, and lipid peroxidation. There was no interaction between age and dose of vitamin E for meat quality characteristics (P > 0.05). The age at slaughter had a quadratic effect (P < 0.05) on pH, brightness, redness, and water holding capacity. Although pH values were higher in the breast meat of older birds (51 and 52 d old), breast meat of younger birds (48 d) had a more reddish aspect. Shear force value was higher in breast meat of birds slaughtered at later ages (P < 0.01), as a linear age-effect was observed. Brightness increased linearly (P < 0.05) with higher vitamin doses, whereas treatments did not alter yellowness, cooking loss, and lipid peroxidation. In this study, increasing vitamin E doses in the finishing period increased the brightness of broiler breast meat, whereas slaughtering at later ages resulted in greater meat pH and shear force value.

Effect of pelleting and different feeding programs on growth performance, carcass yield, and nutrient digestibility in broiler chickens.

This experiment was conducted to study the effect of different feeding programs and pelleting on performance, nutrient digestibility, ileal digestible energy (IDE); and carcass yield of broilers from 21 to 35 d of age. In total, 768 male broilers were distributed according to a completely randomized design with 6 treatments and 8 replicates of 16 birds each. The treatments were mash and pelleted diets provided ad libitum, or pelleted and supplied at the same rate (100%) or restricted at 95, 90, and 85% (P100, P95, P90, and P85) of the amount consumed by the birds fed mash diet ad libitum. When supplied ad libitum, the pelleted diet had the highest feed intake and weight gain (WG), better feed conversion ratio (FCR), better feed conversion adjusted for 2.3 kg (AdjFCR, P < 0.001) and caloric conversion (P < 0.001); and higher amount of abdominal fat (P < 0.001) when compared to the control (mash ad libitum). However, there were no effects on nutrient digestibility (P > 0.05). When the pelleted feed was provided in the same amount as in the control group, there were no differences in any of the evaluated parameters (P > 0.05). Limiting pelleted diet to 95, 90, and 85% of free choice mash diet resulted in lower WG (P < 0.001). P90 and P95 treatments resulted in higher dry matter and crude protein digestibility and IDE in relation to the others (P < 0.001). Carcass yield was reduced (P < 0.05) in the birds fed P85 diet. The regression analysis between P100, P95, P90, and P85 showed a linear reduction in WG when restriction was increased (P < 0.01); however, there was a linear increase in the nutrient digestibility (P < 0.001). It is concluded that pelleting improves broiler performance, but these results depend on feed intake. The higher intake provided by pelleting can increase the amount of abdominal fat. Feed intake reduction can result in lower performance and lower carcass and cuts yield in broilers.

Effect of feeding frequency of a diet containing soya hulls on the food intake and behaviour of dogs.

Dietary fibre may promote satiety and reduce energy consumption per gram of food. Associated with feeding management, dietary fibre may contribute to reduce anxiety in dogs submitted to food restriction to lose weight. The objective of the present study was to evaluate the food intake and the behaviour of dogs fed diets without soya hulls (0SH) or with soya hulls (16SH) once (1×) or twice (2×) daily. Eight adult Beagle dogs, with 11·3 (se 1·6) kg body weight (BW), 4·1 (se 0·1) years of age and body condition score between 4 and 7, were distributed in 4 × 4 Latin square design (n 8/treatment, 5 d/period) in a 2 × 2 factorial arrangement (0SH v. 16SH; 1× v. 2×). Food allowance was 50 % in excess of the daily metabolisable energy (ME) requirements; food residues were weighed. The behavioural test consisted in continuously observations for 24 h, using the scanning sampling technique (observations every 10 min). General behaviours, such as sleeping, barking, standing and others were recorded. Food intake in g/kg BW(0·75) per d of 0SH and 16SH was not different (P > 0·05). However, dogs fed the 0SH diet presented higher (P > 0·05) energy intake (kJ/kg BW(0·75) per d; P < 0·05) compared with those fed the 16SH diet. Dogs fed 2× daily had higher intake, both in g and in kJ, compared with those fed 1 × , independently of diet. There was no interaction between diets and feeding frequency (P > 0·05). No behavioural differences were observed (P > 0·05). The diet containing 16SH, despite reducing ME intake, did not restrict food intake (in g). Dogs fed 1× per d had lower food intake, possibly due to gastric capacity limitation.