Características das fibras musculares de cordeiros nascidos de ovelhas recebendo suplementação proteica no terço inicial da gestação

It was used 80 Santa Ines ewes with average body weight 47.79 ± 3.76 kg, mated with Dorper rams and fed concentrated diet with 15.20; 22.48; 26.52 and 35.65% crude protein (CP) on the initial third of pregnancy. Sheep were kept on aruana grass (Panicum maximum cv. Aruana) pasture during the day. At birth, biopsy on the left Semitendinosus muscle were done on male lambs to evaluate the number and diameter of muscular fibers. During finishing phase, lambs were distributed in two groups and fed control diet with 16.18% crude protein (CP) and 79.64% total digestible nutrients (TDN); without sunflower grain; or fed diet with 9.10% sunflower grain (15.03% CP and 78.96% TDN). There was no effect of maternal feeding on the weight of lambs at birth (4.82 kg), at 30 days of age (9.69 kg) and at weaning (15.38 kg). Sex affected weight of lambs from birth to weaning. Performance of the lambs during finishing phase was not affected by diet given during this phase, neither by the sex nor by maternal food management during pregnancy. There was no difference on number (2,813.45) neither on diameter (13.16 μm) of the muscle fibers on birth. Contents of crude proteins in diets for sheep at the initial third of pregnancy can be reduced because this reduction does not affect diameter and number of muscle fibers.