Improving the Health Status of Pregnant Ewes and their Lambs under Heat Stress Conditions by Feeding Glutamine

Heat stress (HS) affects physiological, biochemical and production functions in livestock. By suppressing various components of the immune system, HS increases the susceptibility of livestock to various diseases. This tension has a negative effect on the health and production ability of livestock by disrupting the nervous-hormonal system and suppressing the immune system. The use of different nutritional solutions to improve the immune system of livestock in different stages of production has attracted a lot of attention. This research was conducted to evaluate the effects of glutamine supplementation and protein level on inflammatory indicators, immune system and blood parameters of pregnant Zel breed ewes during the transitional period and the immune response of their lambs during HS.

20 pregnant ewes with an average weight of 42±1 kg and an age of 2.5±1 years and multiparous were selected and randomly assigned to four experimental treatments. Experimental treatments included: 1) basal diet (equal metabolizable protein requirement) 2) basal diet with glutamine (1% diet) 3) diet with 10% more protein than requirement and 4) basal diet with 10% more protein with glutamine.  Blood sampling was done weekly before morning feeding from all ewes using vacuum tubes containing heparin (Venojet) from the jugular vein. Blood parameters including albumin, total plasma protein, alkaline phosphatase and malondialdehyde were measured with relevant kits and with an automatic analyzer. Insulin, immunoglobulin G (IgG), interleukin 2 (IL-2), interleukin 6 (IL-6) and interleukin 10 (IL-10) were measured using ELISA kits. In order to evaluate the immune response and the state of general inflammation, the differential blood count profile was examined.

One week before and after parturition and on the day of parturition, the amount of albumin, total protein, insulin and IgG increased with glutamine consumption (P<0.05).  Also, glutamine supplementation increased the concentration of IgG in lambs born from ewes (P<0.0001).The effect of experimental treatments on alkaline phosphatase was not significant. Also, the consumption of glutamine supplement one week before parturition, one week after parturition and on the day of parturition decreased the concentration of malondialdehyde (P=0.0030, P=0.0057 and P=0.0301, respectively). The number of white blood cells in one week before parturition and on the day of parturition increased significantly with the addition of glutamine (P=0.0015 and P=0.0024, respectively). Glutamine supplementation significantly reduced blood neutrophils (P<0.05). However, blood lymphocyte was significantly increased (P<0.05). On the day of parturition and one week after parturition, treatments increased the values ​​of IL-2 (P=0.0216 and P=0.0586, respectively) and IL-10 (P=0.0573 and P=0.0019, respectively). While the amount of IL-6 on the day of parturition and one week after parturition was significantly reduced by consuming glutamine and adding the level of metabolizable protein (P=0.0079 and P=0.0027, respectively).

The results of this experiment showed that glutamine supplementation improves the health status of pregnant ewes under HS and their lambs.