Wet citrus pulp in finishing diets for feedlot lambs:

performance and hepatic enzyme concentration

Abstract

Pectin industry generates a citrus pulp residue compounded by peduncle, endocarp, juice vesicles, columella, seeds and tiny fractions of epicarp and mesocarp of citrus fruits, denominated Wet Citrus Pulp (WCP), which has not yet been tested as food for lamb’s nutrition. Thus, this study aimed to determine the effect of partial replacement of ground corn by WCP in high-concentrate diets on the performance and hepatic enzyme concentration of feedlot lambs. Forty-two male lambs (15 Santa Inês and 27 ½ Dorper × Santa Inês), with 24.7 ± 1.5 kg of BW and 60 ± 5 d of age was assigned to a randomized complete block design. Within blocks (n = 14), lambs were randomly assigned to 1 of 3 treatments: 0WCP (control) – diet containing 75.5% ground corn without WCP; 20WCP – diet containing 20% WCP in replacement of ground corn, and 40WCP – diet containing 40% WCP in replacement of ground corn. The experiment lasted 70 days, which was split in 3 experimental periods (14 days of diets’ adaptation and 2 sub-periods of 28 days each). Statistical analyses were performed using the MIXED procedure of the SAS. Orthogonal polynomials for diet response were determined by linear and quadratic effects. There was a quadratic effect for DM, CP, ash, ether extract and NFC intake The highest DM and CP intake was observed for lambs fed 20WCP, however, the control diet increased the ash, ether extract and NFC intake. The increased levels of WCP decreased the ADG and feed efficiency (FE) during the adaptation period, however, did not affect the ADG and FE on periods 1 and 2. Consequently, the increased levels of WCP inclusion decreased linearly the BW. There was no effect of WCP inclusion in diets on Gamma-Glutamyl Transferase (GGT) concentration. However, there was a linear increase for Aspartate Aminotransferase (AST) concentration during the adaptation period, but without difference in other periods. In conclusion, adding up to 40% of WCP in finishing diets for feedlot lambs decrease performance during adaptation period, compromising the final body weight, but without damages effects on liver enzymes.