Effects of a Twelve-Hour Sequential Feeding Cycle with Diets Varying in Amino Acid Content on Performance and Body Composition of Growing-Finishing Pigs

Recent studies have shown that nutrient metabolism, utilization, and excretion may vary during the 24-h circadian period. For instance, greater absorption and utilization of amino acid (AA) in the morning than in the evening has been reported in pigs. In this regard, this study aimed at evaluating the effects of different AA feeding programs over the day on the performance and body composition of growing-finishing pigs. Forty-five 30-kg (± 2.8) BW barrows were assigned to one of three feeding programs (15 animals per treatment): 1) conventional feeding (CONV) in which pigs received 100% of standardized ileal digestible (SID) AA recommendations for the entire day; 2) sequential feeding (SEQ110-70) providing 110% SID AA recommendations from 2400 h to 1200 h and 70% from 1201 h to 2359 h; and 3) sequential feeding (SEQ70-110) providing 70% SID AA recommendations from 2400 h to 1200 h and 110% from 1201 h to 2359 h. The experimental period lasted 84 days subdivided into phase 1 (from d 0 to 35), phase 2 (from d 36 to 63), and phase 3 (from d 64 to 84). Body lean and fat mass were assessed by dual-energy X-ray absorptiometry at the beginning and at the end of each phase. An individual pig was considered the experimental unit, and data were analyzed using the MIXED procedure in SAS including the fixed effects of treatments. Initial BW was included as a covariate. ADFI, ADG and G:F did not differ between feeding programs (P > 0.05). Lysine intake was lower in SEQ-fed pigs than in CONV-fed pigs (16.60 vs 17.82 g/d, respectively, on average; P < 0.05). Feeding program did not affect body lean (61.24 kg for CONV vs 60.71 kg for SEQ, on average; P > 0.05) or fat content (14.46 kg for CONV vs 14.67 kg for SEQ, on average; P > 0.05). Fat gain was greater in individuals fed the SEQ110-70 diet than in those fed the SEQ70-110 diet (240 vs 222 g/d, respectively; P < 0.05); however, there was no difference between individuals in either SEQ group and those in the CONV group (230 g/d; P > 0.05). According to our results, SEQ feeding reduced consumption of AA (lysine) without impairing the performance or body composition of growing-finishing pigs. This feeding strategy may be considered as a potential tool to reduce feed costs and nutrient excretion in pig production.