Meta-analysis of recommended digestible lysine levels for primiparous lactating sows

I congratulate the study team on the researched subject. However, I would like to express my opinion about the meta-analysis study with lactating sows. In addition to a series of details that compromise the analysis and conclusion of the study, such as body condition of the sow at farrowing, variation in the standardized number of piglets per litter, in the feed consumption of sows and duration of the lactation period, as well as the differences in the environmental condition of the hatcheries, we have to consider that the large and expressive majority of works feed the sows freely. In this particular case, although the study concludes about the requirement of digestible lysine, in fact, the differences in the consumption of metabolizable energy and other nutrients also interfere in the responses, but the effects are attributed only to the variation in the consumption of digestible lysine. The opinion expressed here about these studies originated after conducting a study precisely to determine the liini requirement.

As we have already made our study considerations similar to this one regarding the determination of the LD requirement exactly for lactating primiparas, we continue with a similar opinion on the matter as follows;
From my own experience, in an experiment we conducted with primiparae during lactation, in which the feed intake was fixed, based on 95% of the voluntary consumption of a batch of primiparae used for this purpose. This practice aimed to fix the consumption of metabolizable energy between treatments,. The study aimed to evaluate the consumption of digestible lysine in grams per day (g/day), which ranged from 45 to 65g/day (45 g,50g,55g,60g/day). After weaning, management during the weaning interval and during pregnancy were standardized. There was a gradual and consistent improvement, but not significant in the number of piglets born in the second parturition between 45 to 55g of digestible lysine. However, from 55 to 60g/day of digestible lysine (LD), the number of piglets born in the second parturition significantly decreased by 2.2 piglets. With the results obtained, it was concluded that the daily consumption of metabolizable energy (ME) is what defines the level of LD in the diet, according to the ratio that corresponded to 3.16g LD/1000Kcal of ME. Above this value, amino acids will be deaminated due to lack of ME, with production of urea that causes a reduction in uterine PH and causes a negative change in secretion, causing embryo death, which results in a decrease in the number of piglets in the second parturition. Thus, the LD requirement of lactating primiparas varies according to the level of ME in the feed, keeping the LD:ME ratio at 3.16 g LD/1000Kcal.