PS10-19. Prediction Models for in vitro Nutrient Disappearance of Fish Meal for Pigs.

Abstract Fish meal (FM) is often used in nursery pig diets. An accurate determination of nutrient utilization in FM is crucial for precise swine feed formulation. As a more cost-effective alternative to animal experiments, in vitro procedures have been employed to evaluate nutrient utilization of feeds fed to pigs. The objectives were to determine in vitro ileal disappearance (IVID) and in vitro total tract disappearance (IVTTD) of nutrients in FM and to develop prediction models for IVID of dry matter (DM) and crude protein (CP) and IVTTD of DM and organic matter (OM) in FM based on their chemical composition. Eight sources of FM were analyzed for DM, gross energy, ash, CP, and ether extract (EE) concentrations. The FM were tested for IVID and IVTTD of nutrients using a 2-step procedure simulating digestion and absorption in the stomach and small intestine and a 3-step procedure simulating digestion and absorption in the stomach, small intestine, and large intestine of pigs, respectively. Ash, CP, and EE in the FM ranged from 13.8% to 22.1%, 54.8% to 69.8%, and 6.9% to 12.6%, respectively, on an as-is basis. The IVID of CP in FM varied from 75.2% to 89.5% (SEM = 0.5; P < 0.001) and IVTTD of OM varied from 83.3% to 93.5% (SEM = 0.4; P < 0.001). The CP concentration was positively correlated (P < 0.05) with the IVID of DM and IVID of CP, whereas the EE concentration was negatively correlated (P < 0.05) with the IVID of CP, IVTTD of DM, and IVTTD of OM. Prediction models developed for IVID of DM and CP in FM were: IVID of DM (%) = –22.5 + 1.20 × ash + 1.37 × CP (R² = 0.91; P < 0.001); IVID of CP (%) = 60.6 + 0.58 × CP – 1.37 × EE (R2 = 0.92; P < 0.001) where nutrients are in % as-is. Prediction equations for IVTTD of DM and OM in FM were: IVTTD of DM (%) = 35.5 + 0.80 × ash + 0.77 × CP – 0.83 × EE (R2 = 0.75; P < 0.001); IVTTD of OM (%) = 20.8 + 0.99 × ash + 0.93 × CP – 0.82 × EE (R2 = 0.86; P < 0.001). In conclusion, in vitro nutrient disappearance in FM is variable and the chemical composition of FM can be used to estimate in vitro nutrient disappearance of nutrients for pigs.