Effects of microbial phytase, low calcium and phosphorus, and removing the dietary trace mineral premix on carcass traits, pork quality, plasma metabolites, and tissue mineral content in growing-finishing pigs

• Published in: Journal of animal science 2004-09, Vol.82 (9), p.2630-2639
• Main Authors: Shelton, J.L, Southern, L.L, LeMieux, F.M, Bidner, T.D, Page, T.G
• Format: Article
• Language: English
• Subjects: 6-Phytase - pharmacology; Animal Feed; Animal Nutritional Physiological Phenomena; Animal productions; Animals; ash content; barrows; Biological and medical sciences; Biological Availability; blood chemistry; Body Composition - drug effects; Body Constitution; bone strength; calcium; Calcium - administration & dosage; Calcium - pharmacokinetics; carcass quality; dietary minerals; dressing percentage; feed composition; Female; Food industries; Fundamental and applied biological sciences. Psychology; gilts; lean meat; liveweight gain; Male; Meat - standards; Meat and meat product industries; meat quality; metabolites; Minerals - administration & dosage; Minerals - metabolism; nutrient content; Organ Size - drug effects; phosphorus; Phosphorus - administration & dosage; Phosphorus - pharmacokinetics; phytases; pork; Random Allocation; Swine - blood; Swine - growth & development; swine feeding; Terrestrial animal productions; tissue weight; Vertebrates; Weight Gain - drug effects
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/2004.8292630x

An experiment was conducted to determine the effects of phytase addition, reduced Ca and available P (aP), and removing the trace mineral premix (TMP) on growth performance, plasma metabolites, carcass traits, pork quality, and tissue mineral content in growing-finishing swine. One hundred twenty crossbred pigs (initial and final BW of 22 and 109 kg, respectively) were allotted to five dietary treatments on the basis of weight within gender in a randomized complete block design. There were three replications of barrows and three replications of gilts, with four pigs per replicate pen. The dietary treatments were as follows: 1) corn-soybean meal (C-SBM), 2) C-SBM with reduced Ca and aP, 3) C-SBM with reduced Ca and aP plus 500 phytase units/kg of diet, 4) Diet 1 without the TMP, and 5) Diet 3 without the TMP. The Ca and aP were reduced by 0.10% in the low Ca and aP diets and the diets with added phytase. Daily gain, hot carcass weight, dressing percent, kilograms of carcass lean, bone ash percent, and bone strength were decreased (P = 0.10), but liver and kidney weight were increased (P = 0.10) in pigs fed diets with reduced Ca and aP; adding phytase reversed these responses (P = 0.10). The Commission Internationale de I'Eclairage L* was decreased (P = 0.09) in pigs fed the low Ca and aP diet plus phytase relative to those fed the control diet. Removing the TMP had no effect on overall growth performance, but it increased (P = 0.03) 10th-rib backfat thickness and fasting glucose and decreased (P = 0.03) carcass length and ham weight. Liver weight and liver weight as a percentage of final BW were not affected when phytase was added to the control diet, but removing the TMP increased liver weight and liver weight as a percentage of final BW; adding phytase reversed these responses (phytase x TMP, P = 0.06). Removing the TMP decreased (P = 0.08) Zn concentrations in the bone, muscle, and liver, and Cu and Fe concentrations in the bile but increased (P = 0.08) Mn concentrations in the bile and liver of pigs. The addition of phytase reversed the negative effects of the reduced Ca and aP diets. These data indicate that removing the TMP in diets for growing-finishing pigs has no negative effects on growth performance or pork quality, but it had negative effects on carcass traits and had variable effects on tissue mineral content.