Iván Camilo Ospina-Rojas

Supplemental glycine and threonine effects on performance, intestinal mucosa development, and nutrient utilization of growing broiler chickens

A study was conducted to evaluate Gly requirements in low-CP diets with different levels of digestible (dig) Thr, and their effects on performance, intestinal mucosal development, and nutrient utilization of broiler chickens from 21 to 35 d age. A total of 240 twenty-one-day-old Cobb-Vantress male broiler chickens were distributed in a completely randomized 4 × 2 factorial arrangement for a total of 8 treatments with 5 replicates of 6 birds each. The treatments consisted of 4 levels of Gly+Ser (1.47, 1.57, 1.67, or 1.77%) and 2 levels of dig Thr (0.70 or 0.77%, corresponding to 100 or 110% of Thr requirements, respectively). Common diets were fed to broilers until 20 d of age. At d 35, an interaction (P ≤ 0.01) was observed between the Gly+Ser and dig Thr levels for G:F. Glycine supplementation resulted in a linear increase (P < 0.05) in BW gain, G:F, intestinal mucin secretion, apparent digestibility of fat, and AME values of the experimental diets. Threonine levels greater than the levels required (0.77%) improved (P < 0.05) G:F and increased (P < 0.05) intestinal mucin secretion. However, intestinal morphometry and the number of goblet cells in the duodenum, jejunum, and ileum were not affected by the treatments. The dietary Gly+Ser level necessary to optimize G:F in low-CP diets containing 0.77% Thr for broiler chickens during growth was estimated to be 1.54%; however, this requirement may be greater than 1.77% in diets with 0.70% Thr. Supplemental Gly may be essential to support maximum performance for broiler chickens from 21 to 35 d of age when they are fed diets based exclusively on vegetable ingredients and with low protein levels. Glycine can directly or indirectly influence the proper function of the intestinal mucosa and improve dietary energy utilization.

Commercially available amino acid supplementation of low-protein diets for broiler chickens with different ratios of digestible glycine+serine:lysine.

This work studied the effect of supplementing commercially available amino acids in low-protein diets using different ratios of digestible (dig) glycine+serine:lysine (Gly+Ser:Lys) on performance, serum parameters, feathering, and litter characteristics of broiler chickens during the starter period. A total of one thousand fifty 1-d-old Cobb-Vantress male chicks were distributed in a completely randomized experimental design into 6 treatments with 5 replicates of 35 birds each. The treatments were as follows: T1, control diet based on corn and soybean meal formulated with 22% CP (dig Gly+Ser:Lys ratio of 147); T2, diet with a 2% CP reduction, supplemented with Val (dig Gly+Ser:Lys ratio of 137); T3, similar to T2 with the addition of Gly (dig Gly+Ser:Lys ratio of 147); T4, diet with a 3% CP reduction, supplemented with Val, Ile, and Arg (dig Gly+Ser:Lys ratio of 127); and T5 and T6, similar to T4 with the addition of Gly (dig Gly+Ser:Lys ratios of 137 and 147, respectively). At 7 and 21 d, broilers that had received diets with a 3% CP reduction (19% CP) and a Gly+Ser:Lys ratio that was equivalent to 127 had lower G:F (P < 0.05) and lower total protein and albumin serum concentrations (P < 0.05) than those broilers that received the control feed. However, these parameters were restored to the same level as the control diet with an increase in the dig Gly+Ser:Lys ratio from 127 to 137 and 147. Diets with a 3% CP reduction (19% CP) resulted in litter with reduced (P < 0.05) nitrogen content and lower ammonia emission than the litter of broilers receiving the control diet. The treatments did not influence (P > 0.05) the feather length or feathering scores at 21 or 28 d of age. The supplementation of essential amino acids while maintaining dig Gly+Ser:Lys ratios at and above 137 allowed for a reduction in the dietary CP of 3% without undermining the performance, feathering or serum parameters of early stage broilers.

Valine, isoleucine, arginine and glycine supplementation of low-protein diets for broiler chickens during the starter and grower phases

Abstract 1. Two experiments were performed to study the supplementation of valine, isoleucine, arginine and glycine (Val, Ile, Arg, Gly) in low-protein diets for broiler chickens in the starter (1–21 d; Exp. 1) and grower (22–42 d; Exp. 2) phases. 2. A low-crude protein (CP) diet was formulated to meet the requirements of all amino acids (AA) supplied by the control diet except for Val, Ile, Arg and Gly. The other experimental diets were obtained by the isolated or combined supplementation of the studied AA in the low-CP diet. 3. Growth, serum parameters and litter characteristics were taken in both of the experiments. Carcass measurements were taken in Experiment 2. 4. In the starter and grower phases, low-CP diets without supplementation resulted in birds with a poorer weight gain and feed conversion than those of the birds that received the control diet. 5. In the starter phase, individual supplementation with Val and Gly, but not Ile and Arg, restored the weight gain of the birds, while diets with the addition of Val + Gly, Val + Ile + Arg, Val + Ile + Gly and Val + Ile + Arg + Gly restored their feed conversion. 6. In the grower phase, weight gain was re-established at the same rate as the control diet for the diets supplemented with Val + Ile, Val + Ile + Arg, Val + Ile + Gly and Val + Ile + Arg + Gly. However, the feed conversion was restored only in birds that received the diet supplemented with all studied AA. 7. The supplementation of Val and Gly in low-CP diets was sufficient to avoid adverse effects in the performance and serum parameters of broilers in the starter phase. However, birds in the grower phase required the combined supplementation of Val, Ile, Arg and Gly, to prevent compromised performance.

Effects of dietary supplementation of meat-type quail breeders with guanidinoacetic acid on their reproductive parameters and progeny performance

This study was conducted to assess the effect of dietary supplementation of meat-type quail breeders with guanidinoacetic acid (GAA) on their reproductive parameters and progeny performance. Two hundred forty meat-type quails at 25 wk of age were distributed in a completely randomized design with 5 treatments and 8 replicates of 6 birds each. The treatments consisted of 5 dietary levels of GAA (0.00, 0.06, 0.12, 0.18, and 0.24%). The progenies from quail breeders were housed according to breeder treatments and fed a conventional diet based on corn and soybean meal without GAA supplementation. Dietary GAA levels did not affect (P > 0.05) the productivity of meat-type quail breeders, although the concentration of guanidinic compounds (creatine, GAA, and creatinine) in the eggs from the breeders increased linearly (P < 0.05) according to the increase in dietary GAA levels. The number of spermatozoa present in the vitelline membrane was not affected (P > 0.05) by the treatments, but there was a quadratic effect (P < 0.05) of the levels of GAA on fertility, embryonic mortality, and egg hatchability, with the best results estimated at 0.13, 0.15, and 0.14% GAA, respectively. The creatine levels of the pectoral muscle in newborn quails showed a quadratic effect (P ≤ 0.07), and the dietary GAA level of 0.11% was estimated to maximize the muscular creatine level in the progeny. There was a quadratic effect (P < 0.05) of GAA levels on weight gain and feed conversion of progeny at 35 d of age with an optimization point of 0.14% GAA for these variables. Dietary GAA supplementation of meat-type quail breeders increases the availability of creatine in eggs and muscle of progeny, which results in better reproductive parameters and better postnatal progeny performance.

Effect of arginine supplementation of broiler breeder hens on progeny performance

Fernandes, J. I. M., Murakami, A. E., Gomes de Souza, L. M., Ospina-Rojas, I. C. and Rossi, R. M. 2014. Effect of arginine supplementation of broiler breeder hens on progeny performance. Can. J. Anim. Sci. 94: 313-321. Two experiments were conducted to determine the effects of arginine (Arg) supplementation of broiler breeder hens on the performance, carcass yield, and bone measurements of their progeny. In both experiments, the maternal diet was supplemented with five levels of digestible Arg (0.94, 1.09, 1.24, 1.39 and 1.54%). In exp. 1, a total progeny of 1050 chicks were housed in pens according to maternal diet and fed a typical diet without L-Arg supplementation. In exp. 2, a total progeny of 960 chicks were kept in pens according to maternal diet and fed diets containing supplemental L-Arg from 1.30 to 1.90% in the starter phase and from 1.15 to 1.75% in the grower phase. The data obtained in both experiments were deployed in orthogonal polynomials to allow for an analysis of variance and a regression analysis. In the starter phase, there was a quadratic effect (P<0.05) of Arg level in the maternal diet on the feed:gain ratio of the non-supplemented progeny. In the Arg-supplemented progeny, there was a quadratic effect (P<0.05) of Arg level on the feed intake and feed:gain ratio and a linear increase (P<0.05) in body weight gain, and carcass and breast yields (P<0.05). Femur length, tibia diameter, and the Seedor index of both bones increased linearly (P<0.05) in broilers fed the Arg-supplemented diet. Arg supplementation in the broiler breeder hen diets had little positive effect on the non-supplemented progeny; thus, Arg supplementation in the progeny diet is necessary to optimize performance, carcass yield, and bone quality of these hens′progeny.

Effect of dietary restriction and hay inclusion in the diet of slow-growing broilers

The objective of this study was to evaluate the effect of dietary restriction and inclusion of alfalfa (Medicago sativa L.) and Bermudagrass (Cynodon dactylon cv Coastal) hays in the diets of ISA Label JA57 slow-growing male broilers on performance, gastrointestinal tract characteristics, and economic viability. A total of 272 broilers at 21 days old were distributed in a randomized experimental design with four treatments, four replicates, and 17 birds per experimental unit. The treatments consisted of ad libitum concentrated feed (control intake), feed restriction (80% of the control intake), and feed restrictions with supplementation of alfalfa hay (80% of the control intake+20% alfalfa) or Bermudagrass hay (80% control intake+20% Bermuda). Dietary restriction, with and without hay inclusion, negatively affected (P<0.05) the weight gain of the birds; however, feed conversion was improved (P<0.05) for animals that underwent only restricted feeding, which also had the best economic indices. Birds subjected to dietary restriction and inclusion of hays showed changes (P<0.05) in the gastrointestinal organs and intestinal morphology.

Leucine and valine supplementation of low-protein diets for broiler chickens from 21 to 42 days of age

&NA; The objective of this study was to determine the requirements and interactions between the standardized ileal digestible (SID) Leu and Val levels in low‐protein diets, and their effects on performance, serum characteristics, carcass yield and diameter of muscle fibers of broiler chickens from d 21 to 42 posthatch. A total of 1,500 21‐day‐old Cobb 500 male broiler chickens were distributed in a completely randomized design in a 5 × 5 factorial arrangement for a total of 25 treatments with 3 replicates of 20 birds each. Treatments consisted of 5 SID Leu levels (1.0, 1.2, 1.4, 1.6, or 1.8%) and 5 SID Val levels (0.52, 0.67, 0.82, 0.97, or 1.12%). At 42 d of age, there was interaction (P < 0.05) between the SID levels of Leu and Val on feed intake and weight gain. There was a quadratic effect (P < 0.05) of Leu and Val levels on feed conversion, with minimal point estimated at the levels of 1.19 and 0.86%, respectively. Dietary Leu supplementation reduced linearly (P < 0.05) serum concentrations of triglycerides and &bgr;‐hydroxybutyrate. Dietary Leu increased (P ≤ 0.05) the fiber diameters of the pectoralis major muscle and breast yield at the levels of 1.24 and 1.13%, respectively, while the thigh yield was improved with the level of 0.71% Val. Abdominal fat decreased linearly (P < 0.05) with increasing levels of dietary Leu and Val. The SID Leu and Val levels needed to optimize weight gain and feed conversion in low‐CP diets for broiler chickens from d 21 to 42 posthatch were estimated at 1.15 and 0.86%, and 1.19 and 0.86%, respectively. The supplementation of Leu and Val can reduce the abdominal fat deposition in birds fed low‐CP diets during the grower phase. Leu and Val interactions can influence the performance but not the serum characteristics, carcass yield and diameter of muscle fibers of broilers fed low‐protein diets. Therefore, it is necessary to consider the dietary Leu content to estimate the ideal level of Val in low‐CP diets for optimum broiler performance.

Performance, diameter of muscle fibers and gene expression of mechanistic target of rapamycin in pectoralis major muscle of broilers supplemented with leucine and valine

Abstract: Two experiments were performed to study the interaction between the standardized ileal digestible (SID) leucine (Leu) and valine (Val) levels on the mRNA expression of genes involved in the mechanistic target of rapamycin (mTOR) pathway (experiment I) and determine the requirement of these amino acids in low-protein diets, and their effects on performance, serum parameters and muscle fiber diameters of broilers (experiment II) from day 1 to day 21 post hatch. Broiler chickens were distributed in a completely randomized design in a 3 × 3 and 5 × 5 factorial arrangement for a total of 9 and 25 treatments in experiments I and II, respectively. There was no (P > 0.05) interaction between the SID Leu and Val levels on mRNA expression of mTOR, S6 kinase 1 (S6K1), 4E-binding protein-1 (4EBP1), eukaryotic elongation factor 2 (eEF2), and insulin-like growth factor-1 (IGF-1) genes in pectoralis major muscle. Leucine supplementation increased (P < 0.05) mRNA expression of mTOR and S6K1 genes in muscle tissue, whereas Val supplementation did not affect (P > 0.05) mRNA expression of the genes investigated. Interaction was observed (P < 0.05) between dietary Leu and Val levels on feed intake and gain:feed. Leucine supplementation may stimulate mRNA expression of mTOR and S6K1 genes in pectoralis major muscle of broilers from day 1 to day 21 post hatch. The SID Leu and Val levels required for the optimization of feed intake, weight gain, and gain:feed in low-crude protein diets for broiler chickens from day 1 to 21 post hatch were estimated at 1.29% and 0.96%, 1.28% and 0.92%, and 1.27% and 0.91%, respectively; however, these requirements may be greater to maximize muscle fiber growth.

Performance, meat quality and fatty acid profile of broiler chickens fed mixed semi-purified glycerin

The aim of the present study was to evaluate the effects of the inclusion of mixed (animal and vegetable sources) semi-purified glycerin (MSPG) in broiler diets on performance, litter moisture, serum glycerol concentration, carcass and parts yields, meat quality, and the fatty acid profile. In total, 576 1-day-old male Cobb 500 broiler chicks were distributed in a completely randomised design into four treatments (0%, 2.5%, 5.0% and 7.5% dietary inclusion levels of MSPG, as-fed basis), with six replicate pens of 24 birds each. The apparent metabolisable energy corrected for nitrogen balance and energy metabolisability coefficient values of the MSPG were 12.33 MJ/kg DM and 81.61% respectively. There was no significant (P > 0.05) effect of the MSPG concentration on the performance, and carcass and parts yields or broiler meat-quality variables, except for thigh meat colour, in which the yellowness value (b*) decreased linearly (P < 0.05) with an increasing inclusion level of MSPG. Litter moisture and serum glycerol increased linearly (P < 0.05) and the lipid profile of the thigh and drumstick meat of broilers at 42 days of age was slightly altered (P < 0.05) with an increasing MSPG. Mixed semi-purified glycerin can be used at up to 7.5% in broiler diets without impairing performance, meat quality, carcass and parts yields from 1 to 42 days of age. However, special attention should be paid to litter moisture.

DIGESTIBLE VALINE REQUIREMENTS IN LOW-PROTEIN DIETS FOR BROILERS CHICKS

Three experiments were carried out to evaluate the levels of digestible valine in diets with reduced crude protein on the performance, carcass yield and muscle fiber diameter of male broilers during the pre-starter (1 to 8 d of age), starter (9 to 21 d of age) and grower phases (21 to 42 d of age). A total of 1,080 chickens in the pre-starter phase, 900 in the starter phase and 864 in the grower phase were distributed in a completely randomized design with six treatments, consisting of a control positive diet (C+) and diets with 2 percentage points (p.p.) reduction of crude protein level and five graded levels of digestible valine (Val), with six replicates of 30, 25 and 24 birds per experimental unit, respectively. The recommended level of TID Val in the low-protein diets for broilers in the pre-starter, starter and grower stages were 1.028; 0.905 and 0.789%, respectively. The reduction of 2 percentage points of the crude protein level in diets based on corn and soybean meal impaired (p ≤0.05) the feed conversion ratio in the starter and grower stages. Likewise, the reduced-protein diets decreased (p ≤0.05) muscle fiber diameter, but did not affect (p> 0.05) carcass and parts yields, or abdominal fat percentage at 42 days.