Lysine may impair reproductive performance of primiparous sows

Digestible lysine in diets for primiparous lactating sows. ESCOBAR OCHOA, José David, M.Sc Adviser: Juarez Lopes Donzele. Sixty commercial hybrid first litter sows, during lactation (20, 2 ± 0, 13 days), with average body weight of 183, 6 ± 1,46 kg, were used to evaluate digestible lysine intake (DLI) (45; 50; 55 e 60 gr/day). The feed intake was kept at 5.0 kg /day. A completely randomized blocks design, with four treatments (45, 50, 55 and 60 gr DLI/day), fifteen replicates, and the sow considered as the experimental unit, were used. The levels of lysine tested had significant influence on subsequent reproductive performance of sows in the second parity, affecting the number of total born, live born, and litter weight at birth. However, there was no effect of DLI on average piglet birth weight and piglet`s birth weight coefficients of variations on the second delivery. There was no effect of DLI on body reserves mobilization, back fat thickness and muscle depth in sows during lactation. There was no effect on daily body weight gain of piglets and on milk production and composition according to the DLI. It was concluded that the DLI of 42.00 g/day, with a LD/EM ratio corresponding to 2.49 g/Mcal ME, meets the requirements for females during lactation, and the increased lysine intake up to 53.9 g/day, corresponding to a LD/EM ratio of 3.15 g/Mcal ME, results in a higher number of piglets born alive in the second delivery. Regarding the performance of females in the second delivery, it was found that although the evaluated CLD (42.00 to 57.60 g / day) did not influence significantly none of the productive and reproductive parameters evaluated during the lactation, it was found that the treatment corresponding to the consumption of 53.90 g / day (NV), as well as the weight of litter at birth (PLNT) in relation to the treatment females consumed 57.60 g / day of CLD (Table 1). Females submitted to treatments relative to the consumption of 42.00 and 47.60 g / day of CLD, presented of CLD resulted in higher (P 0.05) of the daily CLD of sows was observed in the average birth weight of piglets at second birth. As second MILLIGAN et al. (2002), the average weight of the piglet at birth is inversely related to the number piglets at birth, the fact that in this study the weight at birth did not vary, showed that the development of the embryo was not impaired due to the increased the size of the litter. Like PML, the coefficient of variation of weights of NV piglets (CVPLN) in the second delivery, was not influenced (P> 0.05) by the CLD of the females during the lactation. Although it did not vary, it was found that the litter of the treatments corresponding to the CLD of 47.90 and 53.90 g / day, presented absolute values of CVPLN (12.89 and 12.69) which were on average 18.2% lower than the treatments corresponding to CLDs of 42.00 and 57.90 g / day (15.43 and 15.83) respectively. With based on the results of ZINDOVE et al. (2013), who observed that the uniformity of litter at birth affects the uniformity of the litter at weaning, one can infer females that received 53.9 g of LD / day, despite having higher NT and NV may also show improved performance and uniformity at weaning, thus benefiting the formation of post weaning lots. Based on the report by ALONSO-SPILBURRY et al. (2007) that piglets lower birth weight, whose number increases in higher CVPLN values, are more susceptible to death by starvation or crushing, one can infer from the results obtained in this study, that the increase in litter size obtained in the second with females that consumed 53.90 g of LD, would not compromise the mortality rate. In addition, the reduction in CVPLN with the PLN observed in this treatment would be a important factor in reducing weight variation at weaning and slaughter (WITTENBURG et al., 2011), which would favor production planning by not compromise herd standardization. In this study it was evidenced that, in first-calving females, the interaction between digestible lysine intake and metabolizable energy intake can be a of the factors that most influence the reproductive performance of sows during calving subsequent. It has also been shown that weight losses of less than or equal to 3.9%, during the first lactation do not guarantee adequate reproductive performance at the second as proposed by FONTES et al. (2014), if the relationship between LD/EM is not considered