Regime alimentar para ganho compensatório de ovinos em confinamento: características “in vitro” e “post mortem”.

Abstract

The objective of this work was to determine the effect of diet on characteristics for compensatory gain of "in vivo" (performance, biometry, body condition and scrotal circumference) and "post mortem" (absolute and relative testicular weight, empty body weight, weight of abiotic components of carcass, absolute and relative weight of the gastrointestinal tract, regional and tissue composition of the carcass, morphometry of rumen and small intestines and seminiferous tubules, and hypertrophy of muscle fibers) traits of feedlot lambs. Data were collected from 40 non-castrated Santa Inês lambs kept in individual pens. Lambs were confined during two subsequent periods of 42 days: in a first period each of lambs received one of the four treatments of food restriction (0, 20, 40 and 60% food restriction), and in the second period all the animals were re-fed without restriction. At the end of the confinement period the animals were submitted to a fasting period, weighted and slaughtered just after collection of the “in vivo” traits. After slaughtering, fragments from the rumen, small intestine, testes and semimembranous muscle were collected to evaluate the morphology of the epithelium of the rumen, small intestine and seminiferous tubules, as well as hypertrophy of muscle fibers. The left half of each carcass was sectioned into five primary commercial cuts: neck, shoulder, ribs, loin and leg. The leg was dissected into muscle, bone and fat, and then had his muscularity determined. Dietary restriction followed by re-feeding decreases weight gain, slaughter weight, body length and thoracic perimeter, but does not affect body condition of lambs; decreases body weight and the empty weight of the gastrointestinal tract; lessens the burden of cuts and does not affect your income; also decreases the proportion of carcass fat, thereby producing lighter and cuts meat with less fat; decreases the width of rumen papillae and increases the area of the villi of the small intestine; does not change measures morphometric testicles, the morphometry of seminiferous tubules and the percentage of cross-sections of seminiferous tubules containing the different cells of the seminiferous epithelium of Santa Ines lambs finished in feedlot.