Effekte einer neonatalen Glutamin-Supplementierung auf Wachstum, mRNA-Abundanz ?ausgewählter Tight-Junction Proteine und den Aminosäurenstoffwechsel bei ?Saugferkeln mit niedrigem und normalem Geburtsgewicht

"Effects of a neonatal glutamine supplementation on growth mRNA abundance of selected tight junction proteins and amino acid metabolism in low and normal birthweight piglets"


Continuous breeding for highly prolific sows has resulted in an increase in the number of piglets per litter with low birth weight piglet (LBW). Low birth weight piglets show higher rates of mortality and lower growth. These high mortality rates raise ethical questions about the justification for pig farming, which contrasts with the principles of resource-efficient animal husbandry. Lower growth rates in LBW are linked to economic losses as well as dysfunctional development of the small intestine. Previous studies have demonstrated the beneficial Impact of glutamine supplementation (Gln) on growth and intestinal development parameters in weaned piglets. Since Gln, a conditionally essential amino acid, is intensively metabolized in the epithelial cells of the small intestine, it may potentially normalize the development of the small intestine in LBW.

The study aimed to examine the acute and potential persistent impact of neonatal Gln supplementation in male uncastrated piglets on growth and various parameters of jejunal development.

Male uncastrated suckling piglets in a feeding experiment were analyzed in this trial. The piglets were chosen in pairs from the offspring of gilts based on their birth weight, with selection thresholds of 0.8-1.2 kg for LBW and 1.4-1.8 kg for normal weight piglets (NBW). Selected piglets were supplemented with either 1 g/kg body weight (BW) of Gln or an isonitrogenous amount of alanine (Ala) (1,22 g/kg BW) between the first and 12th day of life. The experimental design resulted in four experimental groups (LBW-Gln, NBW-Gln, LBW-Ala, NBW-Ala), (n = 36/experimental group). The experimental animals had the opportunity to suckle the sow and were offered creep feed starting from the 14th day of life. The piglets´ growth was regularly monitored through weighing and additional zootechnical measurements. One-third of each experimental group was euthanized on the fifth, twelfth, and twenty-sixth day of life, and the distal jejunum, along with chyme, was sampled for further analysis. Animals in the experimental groups received bromodeoxyuridine (BrdU) intraperitoneally one hour prior to euthanasia to assess cell proliferation rate, and L-2H5-phenylalanine to determine fractional protein Synthesis rate (FPSR). In addition, the deuterium oxide method was used to determine milk intake on the eleventh and twenty-fifth day of life in the corresponding groups.

The parameters assessed for jejunal development showed only minor impact by both LBW and Gln supplementation. Notably, the concentration of amino acids from Supplementation was alike in both the sampled jejunal tissue and chyme across groups. Consequently, no distinctions in terms of morphology, immune cell population, and FPSR were observed within the jejunal tissues. No influence of Gln on mRNA abundance of genes regulating amino Acid transport, amino acid metabolism, and glutathione metabolism was detected. Only minor differences were observed between birth weight groups for respective parameters. The age of piglets had the strongest effect on jejunal development parameters. Differences in morphology, amino acid patterns, cell population, nucleic acid concentration, and mRNA abundance of glutathione metabolism genes were observed between twelve-day-old and five-day-old piglets.

From day 11 to day 21 of the study, the BW of LBW-Gln was higher than the BW of LBW-Ala. However, at the end of the study at 26 days of age, there was no difference in BW between LBW-Gln and LBW-Ala. Higher BW of LBW-Gln could only be linked to an increase in jejunal absorptive area, but not to other differences in intestinal developmental parameters. Compared to LBW, NBW had higher growth rate and BW. It was not possible to deduce a negative Impact of LBW on intestinal development based on the measured jejunal development parameters. Additionally, differences in jejunal development parameters, including cell proliferation rate, cell population, and morphology, were observed between 12-day-old and 26-day-old piglets.

In conclusion, oral Gln supplementation marginally improved the growth of LBW piglets, but had very little effect on jejunal development parameters. Furthermore, it was found that low birth weight was not associated with impaired jejunal developmental and which was not responsible for the slower growth of LBW piglets. Finally, it was shown that ontogenetic factors in particular influence jejunal development parameters.