Effect of mother's feeding, physiological state, parity order and offspring's age on their post-mortem pH evolution of longissimus dorsi muscle

The muscle pH evolution and its final value (pHu) have important influence on the keeping qualities of meat, as affecting proteins structures and water holding capacity. Thirty hybrid female rabbits of 15 weeks of age were randomly divided into three groups and fed with one of the three following diets: "C diet" for young females (DE=11.71 MJ/kg DM) was fed ad libitum; "R diet" was fed at 80% of ad libitum (quantitative rationing), "F diet" was rich in fibre (24.6% vs. 18.7% of C diet; DE=9.77 MJ/kg DM) and fed ad libitum (qualitative rationing). The does were inseminated at the 19th week of age. The three diets were administered until the first parturition, afterwards all the does received the C diet ad libitum. The offspring received a commercial pelleted diet balanced for growing rabbits. Two newborn rabbits per litter were chosen at the first and second parturition of does. They were then slaughtered at 36 d of age (weaning) and at 81 d of age, respectively. The trial considered the offspring’s post mortem pH evolution of muscle Longissimus dorsi (LD). To analyze the muscle pH evolution according to the time, pH was measured at 1, 2, 3, 4, 5, 6, 24 hours post mortem. Each measure was performed in duplicate to obtain reliable data. These analyses evaluated the evolution of m. LD post mortem pH according to the offspring’s age (36 and 81 days of age), maternal diet (C, R, F), physiological state (pregnant, non-pregnant), and parity order (first, second). Significant differences (P<0.01) were found in muscle pH according to the age, having younger rabbits higher m. LD pHu reached with lower decline. Quantitative maternal feed rationing originates higher m. LD pHu of offspring of 81 days of age (P<0.01). The physiological state of does had no any effect on the post mortem pH of offspring’s m. LD. Offspring of the first kindling exhibited significantly higher muscle pH from 6 h post mortem onward (P<0.01).