Effect of guanidinoacetic acid supplementation on live performance, meat quality, pectoral myopathies and blood parameters of male broilers fed corn-based diets with or without poultry by-products.

Creatine is a nitrogenous compound naturally occurring in animal tissues and is obtained from dietary animal protein or de novo synthesis from guanidinoacetic acid (GAA). The dietary supply of this semi-essential nutrient could be adversely compromised when feeding purely vegetable-based diets. The objective of this experiment was to evaluate the effects of GAA supplementation in broilers fed corn-based diets with or without the inclusion of poultry by-products (PBP) on live performance, carcass and cut up yields, meat quality, pectoral muscle myopathies, differential blood count, blood clinical chemistry, serum GAA and its metabolites. The treatments consisted of PBP inclusion in the diets at 0 and 5%, with or without GAA supplementation (0 or 0.06%). A total of 1,280 one-d-old male Ross 708 broiler chicks were randomly placed in 64 floor pens with 16 replicates per treatment combination. At 0, 14, 35, 48, and 55 d, pen BW and feed intake were recorded. BW gain and FCR were calculated at the end of each phase. Individual BW was obtained at 55 d and one broiler per pen was selected for blood collection. Additionally, four broilers per pen were selected (including the chicken for blood collection) for processing. Data were analyzed as a randomized complete block design in a 2 × 2 factorial arrangement with PBP and GAA supplementation as main effects. An improvement (P < 0.05) on FCR of 0.019 (g:g) was detected at 55 d due to GAA supplementation. The probability of having breast meat with low severity of wooden breast (score 2) was increased (P < 0.05) by GAA inclusion in diets without PBP. An interaction effect (P < 0.05) was detected on GAA concentration in blood. The supplementation with GAA and PBP inclusion resulted in higher (P < 0.05) GAA serum concentration. Generally, meat quality parameters were not affected by GAA. In conclusion, GAA supplementation improved FCR regardless of dietary PBP and reduced wooden breast severity by increasing score 2 in diets without PBP.

Performance, meat quality, and pectoral myopathies of broilers fed either corn or sorghum based diets supplemented with guanidinoacetic acid.

One experiment was conducted to evaluate the effects of guanidinoacetic acid (GAA) supplementation in broilers fed corn or sorghum-based diets on live performance, carcass and cut up yields, meat quality, and pectoral myopathies. The treatments consisted of corn or sorghum-based diets with or without the addition of GAA (600 g/ton). A total of 800 one-d-old male Ross 708 broiler chicks were randomly placed in 40 floor pens with 10 replicates (20 birds per pen) per each of the four treatments. At hatch, 14, 35, and 50 d, BW and feed intake were recorded. BW gain and FCR were calculated at the end of each phase. Four broilers per pen were selected and slaughtered at 51d and 55d of age to determine carcass and cut up yields, meat quality and myopathies (spaghetti muscle, white striping, and wooden breast) severity in the Pectoralis major. Data were analyzed as a randomized complete block design in a 2 × 2 factorial arrangement with grain type and GAA supplementation as main effects. At 50 d, diets containing GAA improved (P < 0.01) FCR (1.682 vs. 1.724 g: g) independently of grain type. At 55 d, broilers fed corn diets with GAA had higher breast meat yield (P < 0.05) compared to corn without GAA. Drip and cook loss, and shear force (Warner-Bratzler) were not affected (P > 0.05) by GAA supplementation at any slaughter ages. However, GAA decreased (P < 0.05) the ultimate pH at 51 and 55 d in breast meat samples compared to unsupplemented diets. At 51 d, broilers supplemented with GAA had double (P < 0.05) breast meat fillets without wooden breast (score 1) compared with broilers fed non-supplemented diets, therefore reducing the severity of this myopathy. In conclusion, GAA supplementation improved broiler live performance in broilers raised up to 50 d independently of grain source, increased breast meat yield in corn-based diets and reduced the severity of wooden breast myopathy.

Apparent metabolizable energy of by-products from the soybean oil industry for broilers: acidulated soapstock, glycerin, lecithin, and their mixture.

A study was conducted to determine the AMEn contents of fat by-products from the soybean oil industry for broiler chickens. A total of 390 slow-feathering Cobb × Cobb 500 male broilers were randomly distributed into 13 treatments having 6 replicates of 5 birds each. Birds were fed a common starter diet from placement to 21 d. Experimental corn-soy diets were composed of four fat sources, added at 3 increasing levels each, and were fed from 21 to 28 d. Fat sources utilized were acidulated soybean soapstock (ASS), glycerol (GLY), lecithin (LEC), and a mixture (MIX) containing 85% ASS, 10% GLY and 5% LEC. A 4 × 3 + 1 factorial arrangement was used with 4 by-products (ASS, GLY, LEC, or MIX), 3 inclusion levels and 1 basal diet. Each of the four fat by-product sources was included in the diets as follow: 2% of by-products (98% basal + 2% by-product), 4% (96% basal + 4% by-product), or 6% (94% basal + 6% by-product). Birds were submitted to 94, 96, 98, and 100% of ad libitum feed intake; therefore, the differences in AMEn consumption were only due to the added by-product. Total excreta were collected twice daily for 72 h to determine apparent metabolizable energy contents starting at 25 d. The AMEn intake was regressed against feed intake and the slope was used to estimate AMEn values for each fat source. Linear regression equations (P < 0.05) estimated for each by-product were as follow: 7,153X - 451.9 for ASS; 3,916X - 68.2 for GLY; 7,051X - 448.3 for LEC, and 8,515X - 622.3 for MIX. Values of AMEn were 7,153, 3,916, 7,051, and 8,515 kcal/kg DM for ASS, GLY, LEC, and MIX, respectively. The present study generated AMEn for fat by-products data that can be used in poultry feed formulation. It also provides indications that, by adding the 3 by-products in the proportions present in the MIX, considerable economic advantage can be attained.

Effects of incubation temperatures and trace mineral sources on chicken live performance and footpad skin development.

One experiment was conducted to evaluate the effects of two incubation temperature profiles (TEM) and two trace mineral (TM) sources with their inclusion levels on performance and footpad skin development of Ross 708 chickens. A total of 1,000 eggs from 29-wk-old breeders were incubated following two TEM profiles: a standard (S) eggshell temperature (37.8±0.2°C) for 21 d of incubation and an early-low late-high (LH) TEM. The second profile had low (37.2±0.2°C) temperature for the first 3 d, and S until the last 3 d when eggshell temperature was 39.2±0.2°C. At hatch, 15 male and 15 female chicks from each TEM were selected, and footpads sampled. Additionally, 168 males per TEM were placed in 24 battery cages with 7 chickens each. The 48 cages were assigned to two TM dietary treatments: one with inorganic (ITM) sources of Zn (120 ppm), Cu (10 ppm), and Mn (120 ppm) and the other with chelated (CTM) mineral sources using lower inclusion levels of Zn (32 ppm), Cu (8 ppm), and Mn (32 ppm). At 7 and 21 d, BW gain and feed conversion ratio (FCR) were obtained and chicks sampled for footpads. Histological analysis assessed thickness and area ofstratus corneum(SC), epidermis, and dermis. Data were analyzed as a completely randomized block design in a 2×2 factorial arrangement of treatments with TEM and sex as main factors for hatch data and TEM and TM diets for 7 and 21 d data. The LH chicks were heavier than S chicks at hatch, but had more residual yolk. However, S TEM male chickens were heavier at 7 and 21 d. The S TEM had better FCR than LH TEM.Papillaedermis parameters at hatch were higher in the S TEM. At 7 d, SC height and area were increased by the S TEM. At 21 d CTM increased dermis height and area. In conclusion, TEM affected footpad skin development and broiler performance. Replacing ITM with reduced levels of CTM increased dermis development without affecting live performance or other skin layers.

Organic trace minerals and 25-hydroxycholecalciferol affect performance characteristics, leg abnormalities, and biomechanical properties of leg bones of turkeys.

Leg problems and resulting mortality can exceed 1% per week in turkey toms starting at approximately 15 wk of age. Dietary supplementation of organic trace minerals (MIN) and 25-hydroxycholecalciferol (HyD) may improve performance, decrease incidence of leg abnormalities, and increase bone strength. Nicholas 85X700 toms were assigned to 4 treatments consisting of a factorial arrangement of 2 concentrations of MIN (0 and 0.1% of Mintrex P(Se), which adds 40, 40, 20, and 0.3 mg/kg of Zn, Mn, Cu, and Se, respectively) and 2 concentrations of HyD (0 and 92 microg/kg of HyD). Diets were formulated to be equal in nutrient content and fed ad libitum as 8 feed phases. Feed intake and BW were measured at 6, 12, 15, 17, and 20 wk of age. Valgus, varus, and shaky leg defects were determined at 12, 15, 17, and 20 wk of age. Tibia and femur biomechanical properties were evaluated by torsion and bending tests at 17 wk of age. There were no treatment effects on BW. Only MIN significantly improved feed conversion ratio through to 20 wk of age. Cumulative mortality at 3 wk of age was greater among the MIN birds, but it was lower by 20 wk (P = 0.085). The MIN decreased the incidence of varus defects at 17 wk of age; shaky leg at 12, 15, and 17 wk of age; and valgus defects at 15, 17, and 20 wk of age. There were no MIN x HyD interaction effects on individual gait problems. Maximum load and the bending stress required for tibias to break in a 4-point assay were increased with MIN supplementation, especially when HyD was also added. Maximum shear stress at failure of femoral bones in a torsion assay was increased by supplementation with both MIN and HyD together. Dietary supplementation of MIN and HyD may improve biomechanical properties of bones. Dietary MIN supplementation may improve feed conversion of turkeys, likely by decreasing leg problems.

Effects of feed additives and mixed eimeria species infection on intestinal microbial ecology of broilers.

Evaluation of digestive microbial ecology is necessary to understand effects of growth-promoting feed. In the current study, the dynamics of intestinal microbial communities (MC) were examined in broilers fed diets supplemented with a combination of antibiotic (bacitracin methylene disalicylate) and ionophore (Coban 60), and diets containing 1 of 2 essential oil (EO) blends, Crina Poultry (CP) and Crina Alternate (CA). Five treatments were analyzed: 1) unmedicated uninfected control; 2) unmedicated infected control; 3) feed additives monensin (bacitracin methylene disalicylate) + monensin (Coban 60; AI); 4) EO blend CP; and 5) EO blend CA. Additives were mixed into a basal feed mixture, and EO were adjusted to 100 ppm. Chicks were infected by oral gavage at 19 d of age with Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Duodenal, ileal, and cecal samples were taken from 12 birds per treatment just before and 7 d after challenge; 2 samples each were pooled to give a final number of 6 samples total; and all pooled samples were frozen until used for DNA extraction. Denaturing gradient gel electrophoresis was used to examine PCR-amplified fragments of the bacterial 16S ribosomal DNA variable region. Results are presented as percentages of similarity coefficients (SC). Dendrograms of PCR amplicon or band patterns indicated MC differences due to intestinal location, feed additives, and cocci challenge. Essential oil blends CP and CA affected MC in all gut sections. Each EO had different effects over MC, and they differed in most instances from the AI group. The cocci challenge caused drastic MC population shifts in duodenal, ileal, and cecal sections (36.7, 55.4, and 36.2% SC, respectively). Diets supplemented with CP supported higher SC between pre- and postchallenge MC (89.9, 83.3, and 76.4%) than AI (81.8., 57.4, and 60.0%). We concluded that mixed coccidia challenge caused drastic shifts in MC. These EO blends modulated MC better than AI, avoiding drastic shifts after a mixed challenge.

Intestinal microbial ecology of broilers vaccinated and challenged with mixed Eimeria species, and supplemented with essential oil blends.

Intestinal microbiota is an important component in the development of defense mechanisms in the gut mucosa. This project determined the dynamics of intestinal microbial communities (MC) of broilers vaccinated at first day of age with live oocysts of Eimeria species and fed diets supplemented with 2 specific essential oil (EO) blends, Crina Poultry (CP) and Crina Alternate (CA). Five treatments were analyzed: 1) unmedicated-uninfected (UU) control; 2) unmedicated-infected (UI) control; 3) vaccinated with Advent cocci-vaccine and without feed additive (COV) supplements; 4) vaccinated with Advent and supplemented with CP; and 5) vaccinated with Advent and supplemented with CA. The EO blends were added at 100 ppm to the same basal diets. Chicks were gavage-infected at 19 d of age with Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Duodenal, ileal, and cecal samples were taken from 12 birds per treatment just before the infection and 7 d after the challenge, pooled in 6 samples, and frozen. Denaturing gradient gel electrophoresis was used to examine PCR-amplified fragments of the bacterial 16S ribosomal DNA variable region. Results are presented as percentages of similarity coefficients (SC). Dendrograms of amplicon patterns indicated MC differences due to intestinal location, feed additives, and cocci infection. The EO blends CP and CA did affect MC in all gut sections. The cocci-infection caused drastic MC population shifts in duodenal, ileal, and cecal sections (36.7, 55.4, and 36.2% SC, respectively). The CP-supplemented birds had higher SC between pre- and postchallenge MC in duodenal and ileal (73.3, 81.8%) than COV (66.4, 66.5%). However, COV broilers had the smallest changes in cecal MC after infection (79.5% SC). We concluded that cocci-vaccination causes small changes in intestinal MC, but challenge causes drastic shifts. The EO blend supplementation modulates MC in cocci-vaccinated broilers, avoiding drastic shifts after a mixed coccidia infection. Correlations between MC dynamics and host responses are discussed.