47 Quantitative evaluation of hunger in pregnant sows: metabolic and hormonal responses to feeding frequency under limit-fed regime

Abstract

Abstract The objectives of the study were to determine the pattern of glucose, insulin, active ghrelin, and total PYY responses and indirectly quantify perceived hunger in pregnant sows under-limit fed conditions. Eighteen sows [(Landrace × Yorkshire); BW 211.86 ± 1.29 kg; parity 3.80 ± 0.16; backfat 13.50 ± 0.25 mm)] were sampled from 180 sows. Sows were blocked by parity and BW and randomly assigned to 1 of 3 treatments in a RCBD. Treatments included sows fed once at [0730 h (Control, T1), twice [half ration at 0730 and 1530 h (T2)], or thrice [one-third portion at 0730, 1130, and 1530 h (T3)]. The daily feed quantity was kept at 1.25× maintenance energy intake (100 × (BW)0.75) kcal ME/d. Sows received corn-soybean meal-based diet which provided 6935 kcal ME/d and SID Lys:ME of 1.71 g/Mcal from d 30 to 60 of gestation. Hunger was quantified using total area under the curve (AUC) of the hormonal responses. Data analysis was done using PROC MIXED and GLIMMIX procedure of SAS. Sow was the experimental unit. Adjustment for multiple comparisons was by Tukey’s method. The control sows had greater 23-h mean glucose concentration than sows fed 3× daily (P = 0.002). Active ghrelin concentration for sows fed 3× daily tended to be lower (P = 0.063) compared with control sows but reduced (P = 0.018) relative to sows fed 2× daily. In conclusion, sows fed 3× daily had 9.0% reduction in 23-h glucose total AUC, 42.5% greater 23-h insulin total AUC, 27.4% reduction in active ghrelin total AUC, and 14.2% greater PYY total AUC compared with pregnant sows fed 1× daily. It is suggested that hunger in pregnant sows occurs at active ghrelin/total PYY ratio of 5.06 ± 0.20 and at a mean plasma glucose concentration of 70.37 ± 1.39 mg/dL and below.