Suplementação com gordura protegida durante a segunda metade da gestação em ovelhas sobre a expressão gênica, perfil histológico e qualidade de carne da progene

Abstract

Maternal nutrition provided by the availability of nutrients in the diet during pregnancy can directly affect the progeny on performance characteristics and meat quality, a mechanism known as fetal programming. Based on this, the objective was to evaluate the effects of calcium salt supplementation of soybean oil in the maternal diet of crossbred Dorper x Santa Inês ewes during the second half of gestation on maternal and offspring gene expression; as well as the meat quality and histological profile of the offspring. At 75 ± days of gestation, 43 multiparous ewes (44.10 ± 6.87 kg BW, 2 ± 1 parturition) hairless (Dorper × Santa Inês crossbred) pregnant with females (n = 18) and males (n = 25 ), were allocated to individual pens and randomly assigned to the following treatments: (1) Control (CON; n = 21) – supply of a basal diet formulated to meet the basic nutritional requirements of pregnant ewes with a single lamb, or (2) Supplementation ( CSSO; n = 22) – basal diet plus supplementation with Ca salts of soybean oil (rumen-protected fat) receiving daily 1.5g/kg of body weight (5% based on DM. Adipose and muscle tissue of the progeny at 15 days of age and at slaughter for the evaluation of myogenic, fibrogenic, adipogenic, and gluconeogenic markers. At slaughter, samples of the Longissimus lumborum muscle were also collected for determination from the hi profile histological and qualitative aspects of meat. There was interaction (P < 0.05) for area, perimeter and diameter of the progeny muscle fibers, with favorable responses observed for CSSO females compared to the other treatments. There was a trend of sexual dimorphism on the histological profile of subcutaneous adipose tissue, in which females showed ~24% and 12% higher adipocyte area and perimeter (P < 0.10) than males, respectively. However, the fat cell population tended to be ~14% lower (P = 0.08) in females. There was an interaction effect on the relative expression of ZFP423 (P < 0.001) in female progenies from CSSO mothers at birth and PPARy (P < 0.001) for samples at slaughter. Furthermore, the myogenesis of CSSO progenies was affected by having higher mRNA expression for MyOG (P = 0.05). Progenies from CSSO mothers showed lower expression of the type I fiber marker (MyHC I) and higher PPARy (P = 0.01). CSSO progenies showed greater subcutaneous fat thickness (EGS, P = 0.04), maximum fat thickness over Longissimus lumborum (measured GR; P = 0.05) and total losses (cooking and thawing; P = 0.04) that CON Consistent with these responses, higher mean values of visceral fat deposition and carcass coverage (P < 0.001) were observed in females, in addition to higher EGS and carcass GR measure (P = 0.02). Therefore, maternal nutrition with calcium salts from soybean oil during the second half of pregnancy alters fetal growth and trajectory in a sex-dependent manner, due to the modification in the potential for postnatal development of skeletal muscle and subcutaneous adipose tissue.