Dose-response of inactivated yeast in diets of late gestating and lactating gilts on immunoglobulin transfer and offspring preweaning growth performance.

ABSTRACT

Fifty gilts (initial body weight [BW] 190.7 ±â€…4.2 kg) were recruited on day 85 of gestation and were used until day 19 of lactation to assess the dose-response of inactivated yeast via hydrolyzation (HY) inclusion on offspring growth and immunoglobulin (Ig) transfer prior to weaning. Gilts were assigned to one of the 5 experimental diets a control with no HY (HY0) or inclusion of 0.25% (HY0.25), 0.5% (HY0.5), 1.0% (HY1.0), or 1.2% (HY1.2) HY. Gilts were weighed on days 85 and 110 of gestation and days 1 and 19 (weaning) after farrowing. Offspring were weighed on days 1 and 19 of age. On lactation day 1 (approximately 24 h after farrowing), colostrum, gilt plasma, and plasma from 2 median BW piglets were collected and on day 19, plasma from each gilt and 2 median BW piglets per litter were collected for determination of Ig concentrations. Contrast statements were used to assess the linear, quadratic, cubic, and quartic effects of HY inclusion. The inclusion of HY had minimal effects on gilt BW or litter characteristics at birth (total number born and born alive, piglet birth weight). Lactation average daily feed intake of the gilts tended to increase then decrease with increasing HY inclusion (quadratic; P = 0.085). Piglet preweaning average daily gain (linear, quadratic, and quartic; P < 0.05) and BW at weaning (quadratic and quartic; P < 0.05) increased then decreased with increasing HY inclusion. On lactation day 1, colostrum and gilt plasma Ig concentrations were not affected by dietary treatment (P > 0.10) but piglet IgA and IgM decreased then increased with HY inclusion level (cubic; P < 0.05). On lactation day 19, piglet plasma IgG tended to increase with HY inclusion (linear; P = 0.099). In summary, increasing HY inclusion in late gestating and lactating gilt diets improved immune transfer in the first 24 h after birth and piglet preweaning growth rates and BW at weaning. Therefore, maternal feeding of HY could be used as a strategy to improve offspring immunocompetence and BW at weaning, with possible carryover benefits for the postweaning phase.

Abrupt weaning exposes piglets to various stressors that result in a period after weaning with little or no weight gain or feed intake and increased incidence of morbidity and mortality. Inactivated yeast via hydrolyzation (HY) is a functional feed additive that can improve the immune response in pigs. The low and variable feed intakes immediately after weaning render feed additives less useful in nursery pig diets, therefore, enhancing immunocompetence prior to weaning could be a strategy to improve offspring outcomes. This study tested 4 levels of HY (0.25%, 0.5%, 1.0%, and 1.2%) and control (0%) fed to gestating and lactating gilts from day 85 of gestation until day 19 of lactation when piglets were weaned. Plasma immunoglobulin (Ig) concentrations and preweaning offspring growth rates were assessed. It was found that piglet preweaning average daily gain and body weight at weaning were improved with increasing inclusion of HY in the maternal diet, which corresponded to increased plasma IgA and IgM concentrations for the offspring after birth. Greater body weight at weaning and greater plasma IgA and IgM concentration have the potential to attenuate the postweaning growth lag in addition to improving immunocompetence around weaning.