Effects of adding fiber sources to reduced-crude protein, amino acid-supplemented diets on nitrogen excretion, growth performance, and carcass traits of finishing pigs

• Published in: Journal of animal science Vol. 81; no. 2; pp. 492 - 502
• Main Authors: Shriver, J.A, Carter, S.D, Sutton, A.L, Richert, B.T, Senne, B.W, Pettey, L.A
• Format: Journal Article
• Language: English
• Published: Savoy, IL Am Soc Animal Sci 01.02.2003; American Society of Animal Science
• Subjects: Amino Acids - administration & dosage; Amino Acids - pharmacology; ammonium nitrogen; Animal Feed; Animal Nutritional Physiological Phenomena; Animal productions; Animals; barrows; beet pulp; Biological and medical sciences; body weight; carcass characteristics; crude protein; Dietary Fiber - administration & dosage; Dietary Fiber - pharmacology; Dietary Proteins - administration & dosage; Dietary Proteins - pharmacology; Dietary Supplements; excretion; fatty acid composition; Fatty Acids, Volatile - analysis; feces; Feces - chemistry; Female; finishing; Fundamental and applied biological sciences. Psychology; growth performance; isoleucine; low protein diet; Male; methionine; nitrogen; Nitrogen - metabolism; Nitrogen - urine; nutritional intervention; Random Allocation; slurries; soybean hulls; Swine - growth & development; Swine - metabolism; swine feeding; Terrestrial animal productions; threonine; tryptophan; urea; urine; Vertebrates; volatile fatty acids; Monogastric animal; Animal feeding; Fiber; Supplemented diet; Weight gain; Carcass; Body composition; Meat animals; Physiology; Ungulata; Pigs; Macronutrient(mineral); Excretion; Farming animal; Nutrition; Nitrogen; Experimental study; Amino Acids; Pig; Vertebrata; Mammalia; Aminoacid; Artiodactyla; Dietary fiber; Crude protein; Pig Slurry
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/2003.812492x

Two experiments were conducted to evaluate the effects of adding fiber sources to reduced-crude protein (CP), amino acid-supplemented diets on N excretion, growth performance, and carcass traits of growing-finishing pigs. In Exp. 1, six sets of four littermate barrows (initial weight = 36.3 kg) were allotted randomly to four dietary treatments to determine N balance and slurry composition. Dietary treatments were: 1) fortified corn–soybean meal, control, 2) as fortified corn–soybean meal with CP lowered by 4 percentage units and supplemented with lysine, threonine, methionine, tryptophan, isoleucine, and valine (LPAA), 3) same as Diet 2 plus 10% soybean hulls, and 4) same as Diet 2 with 10% dried beet pulp. Nitrogen intake, absorption, and retention (g/d) were reduced (P < 0.04) in pigs fed the low- protein diets, but they were not affected (P > 0.10) by addition of fiber sources to the LPAA diet. However, N absorption, as a percentage of intake, was not affected (P > 0.10) by dietary treatment. Nitrogen retention, expressed as a percentage of N intake, was increased (P < 0.02) in pigs fed the low-protein diets, but it was not affected by fiber addition to the LPAA diet. Urinary and total N excretion was reduced (P < 0.01) by 50 and 40%, respectively, in pigs fed the low- protein diets, but it was not affected (P > 0.10) by fiber addition. However, fiber addition to the LPAA diet tended to result in a greater proportion of N excreted in the feces than in the urine. Slurry pH, ammonium N content, and urinary urea N excretion were reduced (P < 0.10) in pigs fed LPAA, and a further reduction (P < 0.06) in slurry ammonium N content and urinary urea N was observed with fiber addition. Also, fiber addition to the LPAA diet increased (P < 0.02) slurry VFA concentrations. In Exp. 2, 72 pigs were blocked by body weight and sex and allotted randomly to three dietary treatments that were similar to those in Exp. 1, with a corn–soybean meal control diet, LPAA diet, and a LPAA diet with 10% soybean hulls. Pigs were fed the diets from 28.6 to 115 kg, and all pigs were killed for collection of carcass data. Growth performance and most carcass traits were not affected (P > 0.10) by dietary treatment. These data suggest that reducing CP with amino acid supplementation markedly decreased N excretion without influencing growth performance. Fiber addition to a LPAA diet had little effect on overall N balance or growth performance, but tended to further reduce slurry ammonium N concentration and increase volatile fatty acid concentrations.