Effect of excessive lysine on weaned piglets and their intestinal epithelial cells

Email: [email protected] Whatsapp: +86 15054097656?Web: www.sdlachance.net

Lysine is the first limiting amino acid in pig diets, and the required amount of lysine is expressed as a specific percentage in the diet formula. Taking weaned piglets with the bodyweight at 5-10kg?as an example, the requirement of lysine is related to factors such as pig breed, weaning age, diet type and breeding conditions.

?Within a suitable range, the increase of lysine level can promote the absorption and utilization of other amino acids, increase the daily weight gain and feed conversion efficiency of pigs, thereby it can improve the growth performance of pigs. When lack lysine, the body's own protein is degraded, and protein and muscle tissue deposits are reduced. Amino acids can only be used by extra intestinal tissues after being absorbed by the intestines. This is an important step for livestock and poultry to utilize dietary protein.

?Studies have shown that the proliferation and apoptosis of small intestinal epithelial cells is an important part of maintaining the normal physiological activities of cells, and it is very important for the normal function of the intestine. The intestinal epithelial cells of mammals are also the cells with the fastest proliferation and apoptosis in the body, which are renewed every 4 to 5 days on average. This process requires a lot of nutrients. Amino acids can promote cell proliferation, cell apoptosis, cell migration, and maintain intestinal barrier functions.

Studies have shown that glutamine, arginine, leucine and glutamate can accelerate the turnover of intestinal epithelial cell proteins, thereby promoting cell proliferation. At the same time, amino acids can also participate in the regulation of related transport carriers. For example, adding lysine to the diet can significantly increase the expression of bo+ and y+ amino acid transport carriers in the intestine of broilers, and can also significantly up-regulate the expression of amino acids and small peptides in the ileum of fattening pigs. In addition, increasing the concentration of glucose or amino acids alone will also promote the proliferation of fibroblasts.?

?At present, there are few studies on the excessive addition of lysine and related mechanisms of nutrition regulation at home and abroad. This study aims to further explore the effects of adding excessive lysine to the medium of low-protein corn-soybean meal diets and in vitro cultured cells, which can affect the growth performance, organ index, hematological indicators of diarrhea rate, and intestinal epithelial cell proliferation of weaned piglets. The influence of other indicators, and to explore the reasons, provide experimental basis for adjusting the addition of lysine and other amino acids in feed formulations.

?Abstract: To explore the effect of excessive lysine on weaned piglets in vivo and in vitro. In this experiment, 144 Du x Long x Large three-way weaned piglets were randomly divided into 4 groups with 6 replicates in each group and 6 piglets in each replicate (3 steers and 3 sows). Add 1.3%, 2.6%, 3.9% and 5.2% of the standard ileal digestibility lysine (SID Lvs) to the diet to observe its effects on piglet growth performance, organ index, physiological and biochemical indicators.

?Using IPEC-J2 as an in vitro model, adding lysine and other amino acids to determine the proliferation of IPEC-J2 cells according to the types and proportions of amino acids in the culture medium and nutritional requirements, and trying to reduce the adverse effects caused by excessive addition of amino acids by balancing amino acids .

?The results showed that the growth performance of weaned piglets decreased significantly with the increase of dietary SID Lys (P<0.05). The plasma mean corpuscular hemoglobin (mean corpuscular hemoglobin, MCH) part of the serum free amino acid content and intestinal morphology are affected. When 2.0 mmol·L-1 lysine was added to the medium, the cell viability of IPEC-J2 decreased significantly (P<0.05), and the original lysine concentration (0.5mmol·L-1) in the medium was grown by IPEC-J2 Optimal concentration. When supplementing other essential amino acids according to the balanced ratio of amino acids in the culture medium, cell viability is improved to a certain extent; when supplementing with corresponding concentrations of arginine and histidine according to the optimal ratio of pig basic amino acids, cell viability varies with the treatment time The change changes. In summary, adding too much lysine alone will have a negative effect on the growth of weaned piglets, and the balance between amino acids should be fully considered in the actual production and application.

?Results: This study showed that adding too much lysine to the corn-soybean meal diet had a negative effect on the growth of weaned piglets. When fed with 13% SIDLys diet, the growth performance of weaned piglets is the best. When the amount of SIDLys added was 26%, 3.9%, and 52%, the growth performance of weaned piglets decreased, and some blood routine indexes, serum free amino acid indexes and intestinal morphology were all adversely affected. In vitro experiments on IPEC-J2 cells show that lysine greater than 20mmol·L-1 can inhibit the viability of IPEC-J2 cells. In summary, in practical applications, the balance between amino acids should be fully considered.

?