The study aimed to evaluate nutrient digestibility and intestine gene expression in the progeny from cows supplemented during gestation and fed diets with or without rumen‐protected fat (RPF) in the feedlot. Forty‐eight Nellore steers, averaging 340 kg, were housed in individual pens and allotted in a completely randomized design using a 2 × 2 factorial arrangement (dams nutrition × RPF). Cows' supplementation started after 124 ± 21 days of gestation. The feedlot lasted 135 days and diets had the inclusion of zero or 6% of RPF. Digestibility was evaluated by total feces collection. Steers were slaughtered using the concussion technique and samples of pancreas and small intestine were collected immediately after the slaughter to analyze α‐amylase activity, and the expression of SLC5A1, CD36, and CCK and villi morphometry. Feeding RPF increased nutrients digestibility (p < 0.01). There was no effect of maternal nutrition on digestibility and α‐amylase activity in steers (p > 0.05). Duodenal expression of SLC5A1, CD36, and CCK increased in the progeny from restricted cows. In conclusion, protein restriction during mid to late gestation of dams has long‐term effects on small‐intestine length and on expression of membrane transporters genes in the duodenum of the progeny. However, maternal nutrition does not affect digestibility in the feedlot.
The objective was to evaluate the effects of Nellore cows supplementation, during mid to late gestation, on beef quality and expression of genes involved in the deposition of fat and collagen in the muscle of progenies fed diets with or without high inclusion of rumen-protected fat. Forty Nellore steers with an initial average body weight of 340 + 9.38 kg were distributed in a completely randomized design, and arranged in a 2 × 2 factorial design. Therefore, the following treatments were assessed: nutritional management of cows without supplementation (NSUPP); or with supplementation (SUPP: 330 g CP and 2.11 Mcal/cow/day); and progeny feedlot diets without rumen-protected fat (NRPFAT) or with rumen-protected fat (RPFAT: 6% calcium salts). Samples of longissimus thoracis muscle were used for meat quality analyses: pH, color, chemical composition and 14 days aging shear force; and for gene expression analysis using the RT-qPCR. Statistical analyses were done using the GLM procedure of SAS. The maternal supplementation and the use of RPFAT in feedlot diets did not affect muscle pH (5.7; SEM +0.029), L* (40.0; SEM +1.231), a* (11.9; SEM +0.876), fat content (2.3%; SEM +0.306), collagen (1.43 mg/g; SEM +0.08), and shear force (4.2 + 0.322 kgf). However, cows’ supplementation increased the expression of CPT2 and tended to up-regulate FASN and ACACA expression (Table 1). In addition, RPFAT increased expression of COL3A, FN1, IGFR1, and ACACA. There was no interaction effect of cow supplementation on gene expression. These results suggest that maternal supplementation may increase the expression of genes related to lipid synthesis and degradation (lipid turnover). On the other hand, the use of high amount of calcium salts increases the expression of genes involved in collagen synthesis but with no effect on collagen content and tenderness. Funded by Trow Nutrition, Fapemig, INCT-Ciência Animal and Capes.
Background: Rehydration of grains, such as corn and sorghum, is used to increase nutrient absorption. However, the effect of this practice on meat quality is poorly understood. Objective: To evaluate the effects of type of grain and processing on the meat quality of Nellore steers in a feedlot. Methods: Twenty-four non-castrated Nellore steers (270 ± 53 kg initial body weight) were distributed in a completely randomized 2×2 factorial design, with six replicates. The first factor was cereal type (corn or sorghum), and the second was the grain processing (dry or rehydrated and ensiled). The diets were composed of 28.44% corn silage and 71.56% concentrate. Sixty days before the beginning of the experiment, corn and sorghum grains were rehydrated and ensiled. The animals were slaughtered after 140 days of confinement. Meat quality analyses were determined in samples of fresh and aged meat (7 days) from the Longissimus lumborum muscle. Results: no difference between treatments was observed for carcass pH and L* (lightness), a* (redness), and b* (yellowness) values, shear force, thawing and cooking losses, and chemical composition of meat (p>0.05). The b* (yellowness) value of subcutaneous fat was higher in steers fed corn, regardless of grain processing (p=0.03). Sarcomere length was higher in aged meat of steers fed sorghum, regardless of processing method (p=0.01). Conclusions: the grain processing method does not affect beef quality; however, grain type can affect subcutaneous fat color and sarcomere length of aged beef.
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