Effect of Threonine Addition to a Low Protein Diet on IgG Levels in Body Fluid of First-Litter Sows and Their Piglets

First-litter gilts were used to determine how different dietary treatments during gestation affect the reproductive performance of gilts and immunity development of their piglets. Twenty-two crossbred $Landrace{\times}Yorkshire$ gilts were randomly assigned to three dietary treatments, Following conception, the gilts were fed experimental diets until farrowing occurred. The diet for treatment I was low protein diet (8% CP), treatment 2 had an additional supplement of 0.14% threonine that was added to the low protein diet, and treatment 3 was a control diet containing 12% CP. During gestation, net body weight gain of sows in treatment group 2 was higher than in treatment group 1 (p=0,075), However, during lactation there was no difference between all treatments groups on body weight loss and their live piglets at birth. Although milk IgG between treatments did not differ, treatment groups 2 and 3 were slightly higher than treatment group I was, Plasma IgG concentrations in piglets were however equal within all treatment groups at birth and at 7 days of age, at 21 days of age, it was higher in treatment group I than it was in the other two groups (p<0.01), Threonine supplementation to a low protein diet during gestation slightly increases milk IgG of sows, It is beneficial for piglets to acquire more passive immunity, but a suppressive effect was also noted on the endogenous IgG synthesis in piglets. A gestation diet of 8% CP for gilts can stimulate immuno-system of her piglets.