Organic trace mineral levels in the first 96-h post-hatch impact growth performance and intestinal gene expression in broiler chicks.

Alterations in nutrient intake in the avian neonatal posthatch period can impact development, performance, and metabolism in adulthood. Very little is known about how mineral levels during the post-hatch period affect or "program" gene expression patterns later in life. The objective of this study was to determine the effect of post-hatch (0 to 96 h) dietary mineral supplementation on performance, tissue mineral content, and intestinal gene expression profiles in 21-day-old broiler chicks. One-day-old chicks were randomly assigned to one of two treatment groups consisting of N (organic Zn, Cu, and Mn provided at 100 % of recommendations (National Research Council 1994)) and/or L (organic Zn, Cu, and Mn provided at 20 % of recommendations (National Research Council 1994)) diets fed in two intervals (days 1­4, days 5­21) as follows: (1)N­Lor (2)L­L. Performance parameters did not differ between treatments except that body weight gain was greater (P < 0.05) in L­L birds than N­L birds over the experimental period. Bone mineral content was similar for both treatments at day 21. Intestinal gene expression profiling was examined using the Affymetrix GeneChip Chicken genome array. Ingenuity pathway analysis revealed differences in gene expression profiles between N and L treatments at day 5. At day 21, profiles were unique between N­L and L­L, suggesting that the diet fed until day 4 had an impact on gene expression patterns at day 21 even when birds were fed the same diets day 5­day 21. In this study, we demonstrated that diets fed for the 96 h post-hatch had long-term effects on gene expression, providing unique information as to why post-hatch diets are so important for the longterm bird health and productivity.

Effects of yeast cell wall-derived mannan-oligosaccharides on jejunal gene expression in young broiler chickens.

The use of mannan-oligosaccharides (MOS) as alternatives to antibiotic growth promoters (AGP) has gained in popularity in recent years due to regulatory restrictions of using AGP in food animal production. Benefits of MOS usage include improvement on animal performance, feed efficiency, and gastrointestinal health. The molecular mechanisms of these functions however are not clear. The goal of the current study was to use a transcriptomics approach to investigate the effects of MOS on the intestinal gene expression profile of young broilers and characterize biological gene pathways responsible for the actions of MOS. One hundred and twenty 1-d-old Cobb 500 broiler chicks were randomly divided into 2 groups and were fed either a standard wheat-soybean meal-based (control) diet or the same diet supplemented with 2.2 g/kg of MOS (Bio-Mos, Alltech, Nicholasville, KY) for 3 wk, followed by jejunal gene expression profiling analysis using chicken-specific Affymetrix microarrays. Results indicated that a total of 672 genes were differentially expressed (P < 0.01 and fold change >1.2) in the jejunum by MOS supplementation. Association analysis indicated that differentially expressed genes are involved in diverse biological functions including energy production, cell death, and protein translation. Expression of 77 protein synthesis-related genes was differentially regulated by MOS in the jejunum. Further pathway analysis indicated that 15 genes related to oxidative phosphorylation were upregulated in the jejunum, and expression of genes important in cellular stress response, such as peroxiredoxin 1, superoxide dismutase 1, and thioredoxin, were also increased by MOS. Differential expression of genes associated with cellular immune processes, including lysozyme, lumican, ß 2-microglobin, apolipoprotein A-1, and fibronectin 1, were also observed in MOS-fed broilers. In summary, this study systematically identified biological functions and gene pathways that are important in mediating the biological effects of MOS in broilers.

Effects of feeding different concentration and forms of zinc on the performance and tissue mineral status of broiler chicks.

1. Two studies were conducted to investigate the effect of feeding different concentration and forms of zinc (Zn) on the performance and tibia Zn status of broiler chicks. 2. In Experiment 1, chicks fed on the control or the diet supplemented with 12?mg of Zn as sulphate had lower feed intake, weight gain and tibia Zn content than other treatment groups. Chicks given 12 and 24 mg of organic Zn in starter and grower phases, respectively, had the same performance and tibia Zn content as those fed 40 mg of Zn as sulphate and the same performance but higher tibia Zn content than those given 12 mg of Zn as organic over the 42 d. 3. In Experiment 2, chicks given 24 mg organic Zn had greater weight gain than chicks fed on the other treatment diets in the starter period. Chicks fed on the control diet had lower tibia Zn content than chicks fed other treatment diets. Chicks given 80 mg Zn as sulphate had higher tibia Zn content than chicks fed the other treatment diets except those given 40 mg of Zn as sulphate. 4. The results from these trials indicate that feeding lower concentration of Zn as organic form may better promote the growth performance of broiler chicks.

Effects of organic and inorganic dietary selenium supplementation on gene expression profiles in oviduct tissue from broiler-breeder hens.

Selenium (Se) is an essential component of at least 25 selenoproteins involved in a multitude of physiological functions, including reproduction. However, relatively little is known about the mechanisms by which Se exerts its physiological effects in reproductive tissue. The objective of this study was to compare the effect of long-term inorganic Se (sodium selenite, SS) and organic yeast-derived Se (Sel-Plex(®), SP) supplementations on tissue Se content and gene expression patterns in the oviduct of broiler-breeder hens. Hens were randomly assigned at 6 weeks of age to one of the three treatments: basal semi-purified diet (control), basal diet+0.3 ppm Se as SP or basal diet+0.3 ppm Se as SS. At 49 weeks, oviduct tissue from hens randomly selected from each treatment (n=7) was analyzed for Se content and gene expression profiles using the Affymetrix Chicken genome array. Gene expression data were evaluated using GeneSpring GX 10.0 (Silicon Genetics, Redwood, CA) and Ingenuity Pathways Analysis software (Ingenuity Systems, Redwood City, CA). Oviduct Se concentration was greater with Se supplementation compared with the control (P≤0.05) but did not differ between SS- and SP-supplemented groups. Gene expression analysis revealed that the quantity of gene transcripts associated with energy production and protein translation were greater in the oviduct with SP but not SS supplementation. Targets up-regulated by SP, but not SS, included genes encoding several subunits of the mitochondrial respiratory complexes, ubiquinone production and ribosomal subunits. SS hens showed a decrease in transcripts of genes involved in respiratory complexes, ATP synthesis and protein translation and metabolism in oviduct relative to control hens. In this study, although tissue Se concentrations did not differ between hens fed SS- and SP-supplemented diets, expression patterns of genes involved in energy production and protein synthesis pathways differed between treatments. These variations may partially explain the differences in reproductive performance reported in hens fed different forms of Se.

Effects of feeding different forms of zinc and copper on the performance and tissue mineral content of chicks.

A study was conducted to investigate the effects of feeding inorganic or organic Zn and Cu on the performance and tissue mineral content of chicks. A corn-soybean meal diet without Cu and Zn supplementation, containing 31 mg of Zn/kg of diet and 6.6 mg of Cu/kg of diet, was used as a basal diet. Organic Zn (a chelated Zn proteinate) and organic Cu (a chelated Cu proteinate) were used as organic sources for comparison with inorganic reagent-grade sulfates. Supplements provided 20 mg/kg of Zn and 8 mg/kg of Cu. A 3x3 factorial arrangement of treatments consisting of feeding the basal diet with 3 supplements (none, sulfate, or organic) of Cu and of Zn was used. Ten groups of 6 one-day-old male broilers were assigned to each of 9 dietary treatments. Tap water and feed were supplied on an ad libitum basis during the 3-wk trial. The Zn and Cu content in the mucosa of the duodenum of the chick was determined. Dietary supplementation of Zn increased (P<0.01) weight gain, feed intake, and G:F of chicks. The G:F for chicks fed both inorganic sources of Zn and Cu was lower (P<0.01) than that for chicks fed only the inorganic source of Zn. Dietary inclusion of Zn increased (P<0.01) tibia and plasma Zn content. The tibia Zn content for chicks fed organic Zn was higher (P<0.01) than that for chicks fed inorganic Zn. Liver Cu content was decreased (P<0.05) by dietary inclusion of Zn. The Zn and Cu contents in the mucosa of chicks fed the organic source were higher (P<0.01) than those of chicks fed the control diet. The feed conversion data suggest that the antagonism between Zn and Cu occurred when the inorganic forms, but not organic forms, of these 2 minerals were included in a chick diet.

Effects of organic zinc and phytase supplementation in a maize-soybean meal diet on the performance and tissue zinc content of broiler chicks.

1. The purpose of this study was to investigate the effects of Bioplex Zn (a chelated zinc proteinate) and phytase supplementation in a maize-soybean meal diet on the performance and tissue zinc (Zn) content of broiler chicks. Treatment structure consisted of a 2 x 6 factorial arrangement with two inclusions of phytase (0 or 500 PU/kg) and 6 of Bioplex Zn providing 0, 2, 4, 8, 16 and 32 mg Zn/kg diet. A total of 864 chicks were randomly assigned to each of 12 dietary treatments with 6 replicate cages of 12 chicks. 2. Dietary inclusion of phytase increased feed intake, weight gain, plasma Zn content, tibia Zn content, tibia and ash weight. 3. Dietary supplementation of Bioplex Zn linearly increased feed intake, weight gain, gain to feed ratio, plasma Zn concentration, liver Zn concentration, tibia Zn content, tibia and ash weight. 4. An interactive effect of phytase and Bioplex Zn on feed intake, weight gain, tibia Zn concentration and tibia ash weight was found. 5. One slope, straight broken-line analysis of weight gain regressed on the supplemental Zn level provided as Bioplex Zn indicated that 12 mg/kg supplemental Zn without phytase and 7.4 mg/kg supplemental Zn with phytase were required for the optimal weight gain of chicks.

The effect of dietary selenium source and level on the uptake of selenium by developing chick embryos.

We studied the effect of dietary source (organic or inorganic) and level of Se on the Se uptake of chick embryos. After receiving a low-Se diet for 16 wk, 126 Leghorn laying hens were randomly assigned to one of seven dietary treatments. Treatments consisted of feeding a low-Se basal diet alone or with one of three levels of added Se (0.1,0.2, or 0.3 mg/kg Se) supplied by sodium selenite or Se-enriched yeast. Fertile eggs were collected after 33 d of feeding the experimental diets. Eggs were subjected to no incubation or incubation for 5, 10, 15, or 20 d. Non-incubated eggs were separated, and the yolk and albumen were assayed separately for Se. Incubated eggs were separated into the embryo and extra-embryonic portions, which were assayed separately for Se. Se concentrations of the yolk and albumen were significantly different among dietary treatments. Compared with eggs from hens fed sodium selenite, yolk and albumen Se concentrations were higher in eggs from hens fed Se yeast. Embryonic and extra-embryonic Se concentrations were higher in eggs from hens fed Se yeast than eggs from hens fed sodium selenite. The largest increase in embryonic Se concentration was observed during Days 10 to 15 of incubation. It was concluded that Se source and dietary inclusion level influenced the Se concentration of portions of developing embryonated eggs and that embryonic Se concentration changed during incubation.

The effect of dietary crude protein on growth, ammonia concentration, and litter composition in broilers.

An experiment was conducted to determine the effect of diets with reduced CP and supplemental amino acids on broiler performance, N excretion, litter characteristics, and equilibrium NH3 gas concentration. Results suggest that reducing CP (and lysine) below 241 g/kg (13.7 g/kg lysine) in the diets fed during the first 3 wk may slightly increase feed:gain and therefore may not be advisable. During the period 22 to 43 d of age there were no significant differences in weight gain and BW at 6 wk of age when reducing CP from 215 g/kg (11.5 g/kg lysine) to 196 g/kg (11.3 g/kg lysine), but feed intake and feed:gain ratio increased. However, reducing CP did cause equilibrium NH3 gas concentration and litter N to decline by 31 and 16.5%, respectively. Both of these advantages will improve air quality within the housing facility and possibly reduce heating costs during winter associated with higher ventilation rates required to reduce elevated NH3 gas concentrations.

Pearl millet in layer diets enhances egg yolk n-3 fatty acids.

A study was conducted to determine whether substitution of pearl millet for corn in layer diets could enrich egg yolks with n-3 fatty acids. Seventy-two Single Comb White Leghorn hens of a commercial strain in their second cycle of production were fed isocaloric, isonitrogeneous diets (2,860 kcal AMEn/kg and 16% CP) formulated with corn, equal amounts of corn and pearl millet, or pearl millet as the grain source. Each of the three diets was fed to eight replicate groups of three hens for 6 wk. Dietary treatments had no effect on feed intake, BW, egg production, egg weight, and yolk weight. Feeding millet in place of corn significantly decreased yolk pigmentation. The ratio of n-6 fatty acids to n-3 fatty acids in eggs was 13.1, 10.1, and 8.3 for hens fed corn, corn+pearl millet, and pearl millet, respectively. Feeding pearl millet produces eggs significantly (P < 0.05) enriched in n-3 fatty acids.

Effect of dietary aluminum and vitamin D interaction on growth and calcium and phosphorus metabolism of broiler chicks.

The interaction of dietary aluminum (as aluminum sulfate) and vitamin D on growth performance and calcium and phosphorus metabolism was investigated using male broiler chicks. A corn-soybean broiler starter diet, containing .88% Ca and .45% available P and without added cholecalciferol (vitamin D3), was fed with 0 or .2% Al and with 0, 100, or 200 ICU of vitamin D3/kg of diet in a complete factorial arrangement. Four replicate cages of 10 chicks, 1 day of age, were assigned to each dietary treatment. Average body weight gain (328 versus 545 g), feed intake (611 versus 784 g), gain:feed (.54 versus .68), and plasma inorganic P (4.2 versus 6.7 mg/dL) were significantly reduced (P < .05) in chicks fed diets with .2% Al, compared with those fed 0% Al. These four variables were improved by increasing the level of vitamin D3 in the diet from 0 to 100 ICU/kg. However, further improvements were not obtained by elevating the vitamin D3 level to 200 ICU/kg. There were significant interactions of Al and vitamin D3 on gain, feed intake, and gain:feed, but not on plasma P. Gain and feed intake were significantly decreased by Al at each level of vitamin D3. Plasma total Ca was significantly increased by vitamin D3, but was unaffected by Al. Increasing the level of dietary vitamin D3 did not completely alleviate the negative effects of Al.