Ile Supplementation Research Articles

Broiler responses to reduced-protein diets supplemented with valine, isoleucine, glycine, and glutamic acid

SUMMARY Reduced performance is eventually observed when broilers are fed low-protein diets, even when industrial amino acids (AA) are provided to reach requirement levels. The reason for this detrimental effect has not been precisely determined, but it is possible that nonessential AA become limiting below a certain level of protein in the diet. The objective of this study was to evaluate the effects of Val, Ile, Gly, and Glu supplementation, individually or combined, in broiler diets with gradual reductions in protein. A total of 2,016 Ross × Ross 308 male broilers were fed 8 treatments with 9 replications (28 birds per pen) during a 42-d production period. overall care of birds complied with animal welfare directives from the Universidade Federal do Rio Grande do Sul. The control diet (treatment 1) was formulated without restricting CP, maintaining a Gly + Ser:Lys ratio of 155 or 158%. The other treatments, when not supplemented with l-Glu, had a CP content dependent on the fixed ratios of AA to Lys, generating diets with lower CP contents than the control diet. Treatment 2 was formulated with l-Val; treatment 3 with l-Val and Gly; treatment 4 with l-Val + l-Glu; treatment 5 with l-Val + Gly + l-Glu; treatment 6 with l-Val + l-Ile; treatment 7 with l-Val + l-Ile + Gly; and treatment 8 with l-Val + l-Ile + Gly + l-Glu. Dietary CP varied with feeding phase and treatment and reached 2.5% as the greatest reduction obtained. Supplementation of Gly and Glu improved BW gain and feed conversion. Benefits attributable to Gly supplementation were observed mainly in the early phases of growth. Conversely, broilers fed diets supplemented with Glu exhibited advantages in growth throughout experimentation. Addition of Ile, Glu, and Gly increased breast meat yield compared with broilers fed diets supplemented with only l-Val. Supplementation of Ile improved breast meat yield. Good broiler growth and meat yield can be obtained with Gly and Glu supplementation in reduced-CP diets, which implies a need for nitrogen for the synthesis of nonessential AA.

The standardized ileal digestible isoleucine-to-lysine requirement ratio may be less than fifty percent in eleven- to twenty-three-kilogram piglets1

Most studies concerning the Ile requirement in pigs have been carried out using blood products as a protein source, and these have a relatively low Ile content relative to the other branched-chain AA (BCAA). There are indications that an excess supply of one BCAA can affect the utilization of the other BCAA. Little information is available concerning the Ile requirement in pigs when the supply of the other BCAA is moderate (e.g., in cereal- and soybean meal-based diets). The objective of the present study was to evaluate the response of piglets to Ile supplementation under different nutritional conditions. In all experiments, piglets were housed individually and had ad libitum access to feed during a 3-wk period. The first experiment was carried out to study the response of piglets to an increasing Ile supply by using 2 sources of l-Ile differing in degree of purity. Piglets received either a control diet with 48% standardized ileal digestible (SID) Ile:Lys or 1 of 4 other diets containing graded levels of either source of l-Ile to provide 52 or 56% SID Ile:Lys. All diets were formulated to provide 1.00% SID Lys in the diet. Feed intake and growth were not affected by Ile level or Ile source. Experiment 2 was performed to exclude a possible interaction between Ile and Lys supply. In a 2 x 2 factorial arrangement, 2 levels of Lys (1.00 and 1.15% SID Lys) and 2 levels of Ile (48 and 60% SID Ile:Lys) were used. Growth and G:F were 8 and 7% greater in piglets receiving the diet with the greater Lys content, but the Ile:Lys did not affect performance. No interactions were observed between the Lys and Ile supplies. In Exp. 3, a 2 x 2 factorial arrangement was used to test the effect of protein source (spray-dried blood cells or corn gluten meal) and Ile supply (50 or 65% SID Ile:Lys) on performance in piglets. Both protein sources had an elevated BCAA content but differed in Leu and Val contents. Protein source or Ile supply did not affect feed intake, growth, or G:F in the piglets. Plasma concentrations after an overnight fast reflected the difference in AA concentrations of the diets. In conclusion, the results of these experiments indicate that the SID Ile:Lys requirement may be not greater than 50% in piglets receiving cereal- and soybean meal-based diets with a moderate BCAA content. In contrast to other studies, we could not confirm that the Ile requirement was affected by BCAA content of the diet.

Utilization of spray-dried blood cells and crystalline isoleucine in nursery pig diets.

Three experiments were conducted to evaluate spray-dried blood cells (SDBC) and crystalline isoleucine in nursery pigs. In Exp. 1, 120 pigs were used to evaluate 0, 2, 4, and 6% SDBC (as-fed basis) in a sorghum-based diet. There were six replicates of each treatment and five pigs per pen, with treatments imposed at an initial BW of 9.3 kg and continued for 16 d. Increasing SDBC from 0 to 4% had no effect on ADG, ADFI, and G:F. Pigs fed the 6% SDBC diet had decreased ADG (P < 0.01) and G:F (P = 0.06) compared with pigs fed diets containing 0, 2, or 4% SDBC. In Exp. 2, 936 pigs were used to test diets containing 2.5 or 5% SDBC (as-fed basis) vs. two control diets. There were six replicates of each treatment at industry (20 pigs per pen) and university (six pigs per pen) locations. Treatments were imposed at an initial BW of 5.9 and 8.1 kg at the industry and the university locations, respectively, and continued for 16 d. Little effect on pig performance was noted by supplementing 2.5% SDBC, with or without crystalline Ile, in nursery diets. Pigs fed the 5% SDBC diet without crystalline Ile had decreased ADG (P < 0.01), ADFI (P < or = 0.10), and G:F (P < 0.05) compared with pigs fed the control diets. Supplementation of Ile restored ADG, ADFI, and G:F to levels that were not different from that of pigs fed the control diets. In Exp. 3, 1,050 pigs were used to test diets containing 5, 7.5, or 9% SDBC (as-fed basis) vs. a control diet. There were six replicates of each treatment at the industry (20 pigs per pen) location and five replicates at the university (six pigs per pen) locations. Treatments were imposed at an initial BW of 6.3 and 7.0 kg at the industry and university locations, respectively, and continued for 16 d. Supplementation of 5% SDBC without crystalline Ile decreased ADG and G:F (P < 0.01) compared with pigs fed the control diet, but addition of Ile increased ADG (P < 0.01) to a level not different from that of pigs fed the control diet. The decreased ADG, ADFI, and G:F noted in pigs fed the 7.5% SDBC diet was improved by addition of Ile (P < 0.01), such that ADG and ADFI did not differ from those of pigs fed the control diet. Pigs fed diets containing 9.5% SDBC exhibited decreased ADG, ADFI, and G:F (P < 0.01), all of which were improved by Ile addition (P < 0.01); however, ADG (P < 0.05) and G:F (P = 0.09) remained lower than for pigs fed the control diet. These data indicate that SDBC can be supplemented at relatively high levels to nursery diets, provided that Ile requirements are met.

Isoleucine requirement for late-finishing (87 to 100 kg) pigs1

Three pig trials were carried out to determine the true digestible Ile requirement for maximal weight gain and minimal plasma urea nitrogen (PUN) of late-finishing (87 to 105 kg) pigs. In Exp. 1, an Ile-deficient basal diet was developed and confirmed to be markedly deficient in Ile, yet fully efficacious when fortified with surfeit Ile. This diet contained corn and dried red blood cells (RBC) as Ile sources, and was analyzed to contain 10.5% CP, 0.25% Ile, and 0.63% lysine; ME was calculated to be 3,475 kcal/kg. True digestibility of Ile in the basal diet was 88% based on previous digestibility trials in ileal-cannulated pigs and cecectomized roosters. Experiment 2 was a growth trial that involved five graded levels of crystalline Ile supplementation (0.02%) to generate five dose levels of true digestible Ile (0.25 to 0.33%), Diets 1 through 5, respectively. Gain and feed efficiency showed a linear response to incremental doses of Ile (P = 0.003 and 0.036, respectively), with an apparent plateau at 0.31% true digestible Ile. In Exp. 3, a replicated 5 x 5 Latin square, five barrows (Square 1) and five gilts (Square 2) were used in five 4-d feeding periods, with five levels of true digestible Ile (0.22 to 0.30%). Using feed intake as a covariate, a linear decrease in PUN occurred in gilts (8.9, 8.6, 8.0, 7.0, and 5.5; P = 0.004) and in gilts and barrows combined (9.5, 9.2, 9.2, 8.5, and 7.6; P = 0.006) as Ile increased incrementally. The PUN results for barrows (10.5, 10.0, 10.2, 9.9, and 9.7) were not affected by dietary Ile (P = 0.417). The results of these experiments suggest that the factorial requirement estimate of 0.30% true digestible Ile for high-lean, late-finishing pigs suggested by the NRC Subcommittee on Swine Nutrition is accurate.