The usefulness of carbohydrases in corn/soy-based diets for poultry is still unclear and all the more so when phytase is present in the feed. Though there are many interacting factors involved in dictating the measured response to an exogenous enzyme the most influential is the nutritional value of the diet to which it is added. The inherent ileal digestibility of starch, protein and lipid in a corn/soy-based diet varies from around 70% to over 95% and this variance explains up to 90% of the variance in enzyme response. An appreciation for the concentration of undigested starch, protein and lipid in any given diet is an important starting point for the prediction of the effect of the enzyme on digestible energy and amino acids. Instructively, around 15-25% of this undigested fraction can be rendered digestible with the addition of xylanase and so the magnitude of the response is largely explained by the quantity of this undigested portion. As phytase improves the digestibility of the diet, effectively reducing the concentration of undigested amino acids and energy it can be predicted that xylanase will deliver less value in a diet which has already been improved with phytase. It is the purpose of the current paper to describe these effects and the implications for the strategic selection of enzymes for corn/soy-based poultry diets.
The objective of this study was to identify protein markers for tenderness trait of Thai native and commercial broiler chicken muscles. The proteome of chicken muscle with highand low-shear force values was analyzed by two-dimensional gel electrophoresis and MALDI-TOF/MS technique. A total of 169 and 158 protein spots were observed in Thai native and commercial broiler chicken muscles, respectively. Of these proteins, five protein spots were upand down-regulated with low shear force values of chicken meat. Selected three protein spots were identified and showed homology with pyruvate kinase 2 muscle (PKM2), phosphoglycerate mutase 1 (PGAM1) and triosephosphate isomerase 1 (TPI1) of chicken. The PKM2 and TPI1 were correlated with shear force values of chicken meats. Whereas, the PGAM1, B46 and B107 trended toward an association with shear force values. The results indicate that these enzymes of the glycolytic pathway play a major role in the energy metabolism process of muscle and meat characteristics. These findings promote the importance of the muscle metabolic enzymes and could be used as functional candidate genes for meat quality traits in chicken.
A total of 840 male and female birds of Lohman, Hubbard JV, Hubbard classic, and Ross strains were reared from day 1 to 43 to evaluate growth performance, carcass and meat quality traits as influenced by strain, gender, and age at slaughter. All birds were randomly distributed into three pens (35 chicks/pen) for each strain×gender group. At 8, 22, 36, and 43 days of age, 5 birds from each pen were randomly selected and slaughtered. Results showed that Hubbard classic birds had higher (P<0.05) final body weight, overall average daily gain, and most efficient overall feed conversion ratio. Males had higher (P<0.05) overall body weight, average daily gain, and feed intake when compared to females. Female birds had higher (P<0.05) breast cut percentage at 8, 22, and 36 days, and lower leg cut percentage at 22 and 36 days compared to males. Genotype influenced (P<0.05) abdominal fat percentage where Lohman strain had the highest percentage at all slaughter ages. Cooking loss percentage was higher (P=0.0524) for males than females and shear force values were influenced (P<0.05) by strain where meat from Ross was tougher than meat from any other strain, yet generally meat from all strains was considered to be tender. In conclusion, Hubbard classic birds are the most economic of the four strains investigated in this study by having higher growth performance than the other strains tested. However, dressing percentage and meat quality parameters were comparable among the four strains investigated.
Silkie is a famous black-bone chicken breed with beautiful silky feather. The unique medical property of this chicken was recorded in Chinese traditional medicine dictionary about 700 years ago. In this study, we analyzed the mtDNA D-loop sequence variation of 26 Bairong Silkies from Fujian Province, China, together with 100 reported Silkie mtDNAs from China and Japan, and studied their matrilineal components and genetic relationship. A total of 21 haplotypes were detected, which could be assigned to six haplogroups (A-E, G). Among them, haplogroups D and G were exclusively presented in Japanese Silkies and Chinese Silkies, respectively. Chinese Silkies had higher frequency of lineages belonging to haplogroups A, B, and E, and lower frequency of haplogroup C than Japanese Silkies. For the four Chinese Silkie populations, most of samples of Taihe, Chengdu, and Hubei Silkies were grouped in haplogroups A, B, and C, whereas most of Bairong Silkies were grouped in haplogroup E. Five haplotypes were shared by Japanese and Chinese Silkies. The genetic diversity of each Silkie population varied, but the overall diversity of Chinese Silkies was similar to that of Japanese Silkies. Taken together, our results confirmed the genetic connection between Chinese and Japanese Silkies, but also clearly showed that the matrilineal genetic structures of Chinese and Japanese Silkies had some differences.
Coenzyme Q10 (CoQ10), a potent lipophilic antioxidant, is a naturally occurring compound with a ubiquitous distribution in nature, and CoQ10 is used as a dietary supplement to combat aging. There is evidence that lipid soluble nutrients can be transferred into the egg yolk from the feed in laying hens. It is therefore possible that feeding CoQ10 to laying hens increases the content of CoQ10 in the egg yolk. In the present study, we investigated the effect of dietary CoQ10 on its content in the egg yolk of laying hens. Twenty 30 weeks-old Boris Brown hens were assigned based on egg production rate and egg weight to 2 groups (10 birds in each group) and fed a diet containing CoQ10 at 0 or 0.8% for 28 days. Dietary CoQ10 did not affect average egg production rate, feed efficiency, egg weight, and egg yolk weight. CoQ10 content in the egg yolk was increased significantly at 7, 14, 21 and 28 days of the experimental period. Hepatic CoQ10 content and plasma very low density lipoprotein y (VLDLy) CoQ10 concentration in 0.8% group were increased significantly compared with those in 0% group. Dietary CoQ10 significantly decreased cholesterol concentration in the egg yolk at 21st and 28th day of the experimental period. These findings suggest that, in CoQ10-fed laying hens, the increase of hepatic CoQ10 elevates the plasma VLDLy CoQ10 concentration, which in turn results in a high CoQ10 content in the egg yolk of laying hens.
Three experiments were conducted to evaluate broiler chicken performance, ready-to-cook carcass value, and the size of cut-up parts of the left carcass section in response to feeding a corn-soybean meal diet containing graded levels of Litani (L2), Pamir 35 (P2), or Rihan 03 (R6) barley without or with 0.1% enzyme. In the first experiment, a diet containing 25% L2 or R6 without or with enzyme was fed during the finisher period. Enzyme supplementation of the barley containing diets improved (P<0.01) broiler weight gain and feed conversion values. Enzyme containing diets supplemented with 0, 15, 30, and 45% L2, P2, and R6 were fed from hatch to 42d of age in the second experiment. There was a decrease (P<0.06) in cumulative performance with a concomitant increase (P<0.01) in abdominal fat pad yield when the level of barley was increased to 45%. In the third experiment, diets containing 15, 20, 25, 30, and 35% R6 without or with enzyme were fed from hatch till market age. Enzyme addition improved feed conversion and increased abdominal fat pad yield whereas breast muscle and thigh yields were decreased when barley level exceeded 25% (P<0.01). In conclusion, enzyme supplementation to barley diets improved efficiency of feed utilization but increased abdominal fat yield with no significant effect on breast muscle, thigh, and drum yields. The current findings indicate that levels up to 25% of R6 barley could be incorporated in diets up to market age without affecting broiler production parameters.
Coenzyme Q10 (CoQ10), a potent lipophilic antioxidant, is a naturally occurring compound with a ubiquitous distribution in nature and is used as a dietary supplement to combat aging. In rats, there is evidence that coenzyme Q9, major coenzyme Q homologue in rodents, suppresses hepatic cholesterogenesis and decreases plasma total cholesterol concentration. In this study, we investigated the effect of dietary CoQ10 on cholesterol metabolism in growing chickens. The supplementation of CoQ10 in a diet significantly decreased the total cholesterol levels in the liver and plasma. Plasma very low density lipoprotein (VLDL) cholesterol concentration was significantly decreased by dietary CoQ10. The enzymatic activity of hepatic hydroxymethylglutaryl-coenzyme A reductase (HMGR), the rate-limiting enzyme of the cholesterol synthetic pathway, was significantly decreased by dietary CoQ10, whereas the mRNA level of HMGR was not affected. These findings suggest that dietary CoQ10 suppresses hepatic cholesterogenesis by the inhibition of HMGR activity at the posttranscriptional level in chickens, which in turn decreases plasma VLDL cholesterol concentration.
The effects of cultivar on the nutrient profile and protein quality of field pea (Pisum sativum) was investigated. A total of 19 samples representing five cultivars of field pea (Santana, Miami, Rex, Crusader and Courier) were analysed for proximate, fibre and carbohydrate components, minerals and amino acids. Starch was the major carbohydrate component in field pea, but it also contained significant quantities of non-starch polysaccharides. The pea protein was deficient in lysine, methionine, cystine and threonine. The results from the protein quality assay showed that there were no differences (P>0.05) in protein quality between pea cultivars. Compared to raw field pea, raw soybeans had a lower (P<0.05) protein efficiency ratio, and had higher (P<0.05) relative pancreatic weights and mortality rate, suggesting that raw soybeans contained high concentrations of anti-nutritional factors, especially protease inhibitors. Mortality of birds fed raw forms of field pea was low, suggesting that field pea do not have significant levels of any anti-nutrients. The relative pancreatic weights of birds fed pea diets also indicate that the level of protease inhibitors in pea cultivars tested were probably low. Overall, the present results demonstrate the nutritional potential of field pea as a protein source in poultry diets.
Numerous studies in mammalian species have recently been reported that many stem cells have an ability to efficiently efflux the vital DNA-binding dye Hoechst 33342, and it is called side population (SP) cells. However, few study have been reported on the avian SP cells. It could be possible that concentration of hematopoietic stem cells (HSCs) in birds since the characteristic of SP cells should be shared in various tissues and species. In this study, we first attempted the isolation of SP cells from chicken bone marrow and the assessment by gene expression and morphologic analyses. Bone marrow cells (BMCs) were flushed from the femurs and tibias of chicks aged at 10 days with PBS. The BMCs were layered on lymphocyte separation medium and centrifuged for excluding the erythrocytes. The separated cells were adjusted to 106/ml in HBSS. Hoechst 33342 were added (1.25μg/ml) and incubated 60 to 90 minutes at 37°C. Propidium iodide was added (2μg/ml) to exclude dead cells. The SP cells were isolated with flow cytometer. The sorted cells were stained with May-Gruenwald Giemsa (MG) for morphological analysis and RNA was extracted for gene expression analysis. The avian SP cells which was vanished by addition verapamil counld be separated. The percentage of SP cells in chicken bone marrow was about 2.6%. The morphological analysis by MG staining indicated that the SP cells had a larger nuclear and little cytoplasm which were typical characterisation of mouse HSCs. The pattern of gene expressions (CD34, c-Kit, CD4 and CD8) in SP cells also resembled that of the mouse HSCs. These results suggested that the HSCs could be enriched from avian bone marrow cells. Together with these results, it was concluded that SP is one of powerful tools for concentration of avian stem cells.
The present study was carried out to develop a long-term in vitro culture system for chicken primordial germ cells (PGCs). PGCs were obtained from the blood of 2.5-day incubated embryos. GFP gene was transferred into the collected PGCs and then cultured on feeder cells derived from the gonads of 7-day incubated embryos. The GFP-positive cells attached loosely to the feeder cells, and their morphology varied from round to fibroblast-like in shape. They proliferated slowly and occasionally formed colonies. The PGCs cultured for 23-61 days were transferred into the bloodstream of recipient embryos, and we examined their incorporation into the germline of chimaeric chickens. Test mating was carried out, and one germline chimaeric chicken was detected out of 28 putative chimaeric chickens. That one chicken was generated by transferring 58-day cultured PGCs and it produced one donor-derived offspring out of 270 examined. Thus, a small percentage of the cultured PGCs retained the ability to migrate to the germinal ridges, thus giving rise to functional gametes, although most of the cultured PGCs differentiated during the culture period. In conclusion, a germline chimaeric chicken was generated by transferring PGCs cultured in vitro for about 2 months; the culture system for PGCs developed in the present study will contribute to the germline manipulation in chickens.
This study was performed to examine the implications of microgravity on circulating primordial germ cells (PGCs) of the offspring of silky chickens at stages 13 to 17. China's ShenZhou-3 unmanned spaceship was launched on March 25, 2002, at 22: 00 Beijing time (14: 00GMT). The spaceship carried nine fertilized silky chicken eggs (F0) to test the reliability of the life-support system in the space environment. One female and two male chickens were born from these eggs. The three chickens mated naturally and F1 fertilized eggs were collected. Blood was collected from the dorsal aorta or the marginal vein of the embryos at stages 13 to 17, and the number of circulating PGCs of F1 offspring was counted. A similar experimental protocol was performed for the control group (C1 and C2 group). No differences were observed except at stage 15, when the F1 offspring of the flight group (F0 group) showed higher PGC concentrations than the other treatment groups. These results indicated that microgravity may have little effect on the migration and concentration of PGCs in F1 offspring, perhaps because the flight chickens were raised to maturity on Earth under a gravity of 1×g and had sufficient time to recover. Thus, microgravity appeared to have little effect on the PGC concentrations of F1 offspring of silky chickens during circulating stages 13 to 17.
At day 7 of incubation, eggs were injected with high levels of steviol (1.5 and 3mg per egg). At hatch, no effect of steviol injection was observed on plasma thyroid hormone levels, hatchability, body weight and chick quality. Proportional liver weight of chicks receiving the highest steviol dose was significantly higher, while the proportional bursa weight of the steviol injected groups was significantly lower compared to that of the control. Moreover, plasma lactate dehydrogenase activity of chicks from the highest steviol injected group was significantly higher compared to control values. At 7 days of age, proportional liver weight of chicks of the 3mg steviol injected group was significantly lower compared to that of the control treatment. It is concluded that injection of a high dose of steviol has no effect on plasma thyroid hormones and has only slight and temporary metabolic effects on the chicken embryo.
Avian beta-defensins (avBDs) play significant roles in the innate immune system. The aim of this study was to identify immunoreactive (ir) avBDs proteins in the hen ovarian follicles and the changes in their localization with follicular growth. The ovarian follicles at different growth stages, namely the largest (F1), second and third largest (F2 and F3), prehierarchal small yellow and cortical follicles, were collected. The presence of ir-avBD-8, -10, and -12 were examined by immunohistochemistry and Western blot. The three ir-avBDs showed a similar pattern of immunostainings in the follicular tissues at different growth stages. In the granulosa cells, the ir-avBDs were identified in the cortical follicles, whereas their density was reduced in small yellow follicles. The granulosa cells of yellow follicles (F3-F1) showed dense immunolabelings. The interstitial cells showed a faint immunolabeling for avBD-12 but not for avBD-8 and -10 in the cortical follicles, whereas they were weakly stained in the small yellow follicles. Dense immunoreaction products were noticed in the theca interna cells of F3F1 follicles. Western blot analysis showed a single band for each defensin. These results suggest that avBD-8, -10 and -12 proteins are expressed in the specific cells in the follicles, namely interstitial or theca interna cells and granulosa cells, where their amounts are likely increased with follicular growth. These avBDs may play significant roles in the host innate immune system in the follicles.
Morphological characteristics of symmetrically developed ovaries observed in a 17-day incubated chicken embryo were analysed. The size and shape of the left and right ovaries were almost the same, but in histological analysis they have less developed cortex and many large lacunae in the medulla compared to a normal left ovary. The histological structure of both the left and right ovaries was, thus, incomplete compared with the normal left ovary, probably due to the effect of the right ovary developing similar to the left ovary without regression.
The protective effect of orally administered Curcuma longa (turmeric), Capsicum annuum and C. frutescens (hot pepper), and Lentinus edodes (shiitake mushroom) on avian coccidiosis was evaluated in young broilers. Broiler chickens were continuously fed with a standard diet or standard diet supplemented with Curcuma, Capsicum/Lentinus or Curcuma/Capsicum/Lentinus from hatch and body weight gains, fecal oocyst shedding, antibody titers, and pro-inflammatory cytokine gene expression were measured as parameters of protective immunity following challenge infection with E. acervulina. Chickens fed the Curcuma/Capsicum/Lentinus-supplemented diet showed significantly improved body weight gains compared with birds on the standard diet or birds given Capsicum/Lentinus-supplemented diet following challenge infection with E. acervulina. Chickens fed the Curcuma/Capsicum/Lentinus-supplemented diet shed significantly reduced fecal oocysts and produced higher serum antibody titers compared with the groups fed the standard diet or fed Curcuma or Capsicum/Lentinus. Finally, the levels of local cytokine transcripts of IL-1β, IL-6, IL-15, and IFN-γ were consistently greater in the Curcuma/Capsicum/Lentinus-fed group compared to the controls fed only the standard diet, Curcuma, or Capsicum/Lentinus groups. This study provides first immunological evidence that dietary supplementation of turmeric, hot pepper, and shiitake mixture significantly enhances local innate immunity and provides higher protective immunity against E. acervulina infection.