Serum hormone concentrations and performance of sows fed on diets containing peas

The effect of feeding peas at 21.4% (diet 2) and 30.9% (diet 3) of the ration in place of soyabean oilmeal and some of the maize (standard diet I) was investigated in 15 crossbred sows divided into three groups. The isonitrogenous, isocaloric diets were offered throughout gestation and lactation and were consumed in very similar amounts. Determination of serum hormone concentrations (triiodothyronine, thyroxine, cortisol, progesterone, insulin! as well as insulin-like growth factor-I (IGF-I) at mid and late gestation, several days after parturition and 1 day after weaning the litter indicated more intensive anabolism in the groups of sows fed peas than in the control group. Thus, alterations in the diet had little effect on thyroid and steroid hormone concentrations, whereas both preprandial insulin and IGF-I levels tended to be higher in the pea fed groups especially during lactation (P < 0.05). The overall performance in terms of number of weaned piglets tended to be best in the group of sows fed on diet 2 which farrowed more piglets than those fed on diet 3, of greater body mass than those farrowed by the control group. Piglet losses were greatest in the control group. As indicated by the performance and metabolic parameters examined, it seems that nutrient availability was progressively greater in the pea containing diets expressed as a slightly greater number and mass of weaned piglets in the group of sows fed on diet 2 and a somewhat greater increase in sow body mass over the whole reproductive cycle in those fed on diet 3. These tendencies were further manifested in the different peripheral serum hormone profiles found in the different groups. They need to be confirmed and elucidated in experiments with a larger number of animals.