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SUMMARY The objective of this study was to investigate the impact of long-term inclusion of the trace elements zinc, copper, and manganese chelated with the hydroxy analogue of methionine on layer performance, eggshell quality, tibia breaking strength, and immune response. A total of 216 Hy-Line W-36 laying hens were allocated to 6 treatments with 36 pens/treatment and 1 hen/cageusingarandomizedcompleteblockdesign.Therewere6treatmentswithsupplemental Zn-Cu-Mn, as follows: T1 0-0-0 ppm, T2 20-5-20 ppm as sulfates, T3 20-5-20 ppm as chelates, T4 40-10-40 ppm as sulfates, T5 40-10-40 ppm as chelates, and T6 80-10-80 as sulfates. The feeding of dietary treatments started at wk 24 pullet age and measurements of the key parameters were made from wk 44 to 80. Overall results (one-way ANOVA) indicated a significant treatment effect (P 0.05) response to T1 and T6 but different (P < 0.05) from T2. Factorial analysis of the data showed an improvement in shell breaking strength (P < 0.05 at wk 68), shell thickness (P = 0.08 at wk 68; P = 0.03 at wk 74), tibia breaking strength (P = 0.07) and antibody (Ab) titers to SRBCs (P < 0.05 at wk 63; 1 wk after secondary antigen challenge) in hens fed chelated trace mineral when compared to inorganic trace minerals. In summary, feeding laying hens’ diets containing supplemental chelated trace minerals showed improvements in eggshell thickness and immune response when compared to inorganic salts at specific time points measured during the latter part of the laying cycle.

SUMMARY The microbial community of the gastrointestinal system has an enormous impact on the vertebrate host. The relationship begins at birth or hatch and evolves to a stable ecosystem in which diverse, and unique, niches are created and inhabited by microorganisms. These microbial populations tend to be similar within a host species (and even across host species), but each system is a unique construct resulting from its individual history of mutual influence. The development of the system, both microbial and host, begins in the perinatal animal. The timing of this developmental process is suggestive of imprinting, the process of epigenetic evolution of somatic stem cells. (Imprinted changes are thought not to involve the germ line, i.e., are not inherited by the next generation of the host animal, but are genetic changes that can be passed on to the daughter cells of the imprinted proliferative stem cell.) This review briefly discusses the development of the gastrointestinal system, including both the microbiota and its perinatal host. The effects of the microflora on enteric and immune cells are described. Effects of attempts to restrict contact between the mucosal immune system and the microbiota are addressed, along with further data that would be required to demonstrate that the effects of the gut microbiota on mucosal immune development are restricted to an ontogenetic window. Finally, the consequences of a failure to achieve a relationship of mutual tolerance between the microbiota and the host and some mechanisms to facilitate this process are discussed.

Mintrex Zn, Mintrex Cu, and Mintrex Mn organic trace minerals contain 16% Zn, 15% Cu, and 13% Mn with 80, 78, and 76% 2-hydroxy-4-(methylthio)butanoic acid (HMTBA) by weight as the organic ligand, respectively. Our objective was to determine if HMTBA from Mintrex was fully available as a Met source. In experiment 1, thirty-six broilers (7 to 10 d old) were orally gavaged with methyl-(14)C-labeled HMTBA, either as free HMTBA (Alimet feed supplement) or Zn bis(-2-hydroxy-4-methylthiobutyrate) (Mintrex Zn). Radiolabel incorporation from either source into protein was measured as a marker of bioavailable Met activity. Results demonstrated that the HMTBA from Mintrex Zn was equally available as free HMTBA to support protein synthesis. In experiment 2, five hundred seventy-six 1-d-old broilers were allotted to 12 dietary treatments (TRT) for a 21-d growth assay. A TSAA-deficient diet containing 0.70% total TSAA (TRT 1) was supplemented with 0.05, 0.10, 0.15, and 0.20% free HMTBA (TRT 2 to 5) to establish the standard Met response curve. Treatment 6 was analogous to TRT 2 but had an additional 160 ppm Zn, 80 ppm Cu, and 160 ppm Mn as sulfates. Treatments 7 to 12 were identical to TRT 2 but supplemented with 40 or 160 ppm Zn from Mintrex Zn, 20 or 80 ppm Cu from Mintrex Cu, or 40 or 160 ppm Mn from Mintrex Mn, respectively. For TRT 1 through 6, growth performance increased due to increasing Met addition (P < 0.01) but not to increasing inorganic trace minerals. For Mintrex Zn, Cu, and Mn (TRT 7 to 12), there was a linear increase in cumulative gain:feed ratio (P < 0.04), and for Mintrex Zn and Mn, there was a linear increase in cumulative gain (P < 0.03) to increasing Mintrex addition. A 1-slope broken-line model was used to calculate bioavailable Met activity from Mintrex for comparison with actual intake values. Results indicated that HMTBA from Mintrex was fully available as a Met source.

The objective of this study was to compare the gain-response curve to dietary levels of 2-hydroxy-4(methylthio) butanoic acid (HMTBA) and DL-Met (DLM) across 4 floor pen trials in which different diets were used. Six replicates of 38 or 41 birds per pen (trials 1 to 2 and 3 to 4, respectively) were used in a 2 x 3 factorial arrangement. A control with 12 replicates was also included. The 2 Met sources were fed at 3 equimolar levels equally spaced, with the highest level added at requirements from 1 to 48, 49, 43, or 49 d for trials 1, 2, 3, and 4, respectively. Commercial-type TSAA-deficient control diets contained sorghum, wheat, corn, or corn plus meat and bone meal for trials 1, 2, 3, and 4, respectively. Performance improved at all times for most parameters after supplementing with HMTBA or DLM (P0.05). No differences were found in the birds fed HMTBA or DLM at any age and trial (P0.05), except for trial 1, in which 17-d-old birds performed better when fed HMTBA than DLM (P0.05). In each trial, linear, quadratic, and exponential regressions were conducted upon the gain response of birds fed HMTBA and DLM separately. Equations with better goodness of fit were used to compare the estimated gain responses to feeding HMTBA vs. DLM. In 3 trials, the shape of the gain-response curve differed when feeding HMTBA vs. DLM. In trials 3 and 4, feeding HMTBA at commercial levels resulted in greater gain responses than DLM (P0.05), whereas, in trials 2 and 4, at very deficient levels, DLM-fed birds outperformed those fed HMTBA (P0.05). When the 4 trials were combined, the dose-response curve with the best goodness of fit was linear for HMTBA and quadratic for DLM. It can be concluded that the 2 Met sources have a different dose-response form, HMTBA could outperform DLM at commercial levels, and DLM could outperform HMTBA at deficient levels.

The objective of this research was to evaluate the effect of early feeding on the development of the immune system in broiler chicks. A hydrated nutritional supplement formulated specifically for the first 2 to 3 days of post-hatch life was provided to the chicks on the day of hatch and the 2 subsequent days. The nutritional content of this supplement was optimized to achieve maximum performance at 6 wk following ad libitum consumption of starter feed and water. Control hatchlings received neither feed nor water. After the initial treatment, all birds were fed the same corn-soy diet ad libitum. Immune development was assessed by measuring bursa weight, biliary immunoglobulin A (IgA) levels, appearance of germinal centers in the cecal tonsils, and resistance to an oral challenge with coccidial oocysts. Data indicate that provision of the optimum balance of nutrients immediately after hatch result in heavier bursa weights, earlier appearance of biliary IgA and germinal centers, and an improved resistance to disease challenge.