The Japanese captive population of Japanese crested ibis (Nipponia nippon) was established using 5 founders derived from the Chinese captive population. Its size has increased rapidly, and the maintenance phase is about to start. Thus, this study was designed to perform genetic analyses in this population with pedigree information, considering the adoption of mean kinship strategy as the breeding strategy suited to the maintenance phase. Because the relationships among the 5 founders were unknown, different assumptions were set up ranging from 0 to 0.25 of kinship coefficients between the 5 founders. Assuming that the 5 founders were non-inbred in all the assumptions, the results showed that the gene diversity and the mean inbreeding coefficient would fluctuate largely from ∼65% to ∼82% and from ∼0.07 to ∼0.29, respectively. Moreover, the genetic importance of individuals based on mean kinship shifted largely. This study suggested that the Japanese captive population had low gene diversity and high mean inbreeding coefficient even under the assumption that the 5 founders were unrelated and non-inbred. In addition, the study also suggested that it became more effective to analyze the genetic status and to introduce mean kinship strategy into this population with more credible molecular evaluation of the relationships among founders.
The present study was conducted to examine effects of long-term graded L-arginine supply on growth development, egg laying and egg quality in four genetically diverse purebred layer lines. The study comprised a rearing trial from hatch to week 16 and a following laying performance trial from week 17 to 41. After hatch 150 one-day-old female chicks of each genotype were distributed to three diets. The experimental diets were equivalent to 70, 100 and 200% L-arginine of age-specific recommended level (National Research Council, 1994) and were offered ad libitum to chicks (hatch to week 7), pullets (week 8 to 16) and hens (week 17 to 41). However, hens’ diets were quite low in crude protein. After a pre-laying period from week 17 to 21 thirty-six pullets of each group were used further in the laying performance trial. Independent of chicken’s genetic background, insufficient L-arginine supply caused lower body weight, daily weight gain and daily feed intake during the rearing (p<0.001) and induced lower laying intensity and daily egg mass production in the laying period (p<0.05). Parameters fitted to Gompertz function suggested higher adult body weight in L-arginine supplemented birds compared to insufficient supplied ones (p<0.01). Groups fed with insufficient L-arginine reached age of maximum daily weight gain later and showed lowest maximum daily weight gain (p<0.001). As a consequence of limitations in dietary L-arginine and crude protein, high performing genotypes decreased strongly in body weight, daily feed intake and performance compared to the low performing genotypes. In conclusion, L-arginine modified the amount of weight gain and feed intake, especially in growing chicks and pullets independent of genetic background. The high performing hens were more nutritionally stressed than the low performing ones, because concentrations of dietary crude protein were relatively low.
The present study aims to compare the relative bioavailability (RBV) of 1α-hydroxycholecalciferol (1α-OH-D3) to cholecalciferol (D3) in 1- to 21-d-old broiler chicks fed with calcium (Ca)- and phosphorus (P)-deficient diets. A total of 400 male of 1-d-old Ross 308 broilers were randomly assigned to 8 treatments with 5 replicates each. Five levels of D3 (0, 2.5, 5, 10, and 20 μg/kg) and three levels of 1α-OH-D3 (1.25, 2.5, and 5 μg/kg) were added to a basal diet. The basal diet contained 0.50% Ca and 0.25% non-phytate phosphorus (NPP), without D3. The RBV of 1α-OH-D3 to D3 was determined by the slope ratio method. Using body weight gain, feed intake, feed efficiency, and plasma Ca as criteria, the RBV of 1α-OH-D3 to D3 were 4.78, 4.75, 4.50, and 4.21, respectively. Using tibia breaking-strength, weight, length, width, ash weight and content, and Ca and P content as criteria, the RBV of 1α-OH-D3 to D3 were 5.58, 5.16, 4.42, 4.70, 5.03, 4.46, 4.70, and 4.79. Using femur weight, length, width, ash weight and content, and Ca and P content as criteria, the RBV of 1α-OH-D3 to D3 were 5.09, 4.43, 3.19, 5.83, 5.21, 5.27, and 5.31. Using metatarsus weight, length, width, ash weight and content, and Ca and P content as criteria, the RBV of 1α-OH-D3 to D3 were 5.00, 4.05, 5.94, 4.73, 5.33, 5.64, and 4.28. These data indicate that the RBV of 1α-OH-D3 to D3 is 4.84 in promoting growth performance and bone mineralization in broilers from 1 to 21 d of age.
Growth hormone-releasing hormone (GHRH), a stimulator of growth hormone (GH) secretion, is known to have several physiological roles such as the regulation of feeding behavior in mammals. Recently, we have reported that central injection of chicken GHRH decreased food intake in chicks, however, its peripheral role on feeding behavior has not been clarified. The purpose of the present study was to investigate the effect of peripheral injection of GHRH on feeding behavior in chicks (Gallus gallus). Intraperitoneal (IP) injection of GHRH47 (1 nmol), full length form of chicken GHRH significantly decreased food intake in chicks although the injection of GHRH27 and GHRH27-NH2, short forms of chicken GHRH had no effect. The IP injection of GHRH47 did not induced any abnormal behavior, suggesting that GHRH47-induced anorexia might not be related to abnormal behavior such as sleeping, hyperactivity and convulsion. The anorexigenic effect of GHRH47 seemed not to be related to GH because IP injection of bovine GH did not affect feeding behavior in chicks. Collectively, these results suggest that peripheral GHRH is related to inhibit feeding behavior in chicks.
Previously, we showed that the growth of chicks fed a diet containing 43% whole-grain paddy rice and 10% soybean oil was retarded relative to a control group fed a corn-based diet containing 6% soybean oil. However, feeding chicks with 43% whole-grain paddy rice containing 6% soybean oil resulted in normal growth. It is possible that the observed growth retardation was caused by the high soybean oil content or resulted from the combination of whole-grain paddy rice and the high level of soybean oil which was added to the diet to maintain the overall energy content. The present study was therefore carried out to identify the reasons for the observed growth retardation. Thirty-six chicks (0-day-old) were divided into six equal-sized groups that were fed one of the following six experimental diets ad libitum for 28 d: two kinds of dehulled rice-based diets containing 5% or 10% soybean oil (DS5% or DS10%), another three whole-grain paddy rice-based diets containing 10% soybean oil, corn oil, or rendering oil (WS10%, WC10%, WR10%, respectively), and a WS10% diet supplemented with vitamin B12, methionine and ethoxyquin. The body weight gain of groups fed the WS10% and WC10% diets was significantly lower than the weight gain of birds fed the DS5% diet (control). In addition, the liver of birds fed the WS10% and WC10% diet exhibited significantly higher lipid peroxidation than that of the control group. In comparison, supplementation of the WS10% diet with vitamin B12, methionine and ethoxyquin dramatically improved growth and hepatic oxidation status. These results indicate that diets combining whole-grain paddy rice and high levels of soybean and corn oil adversely affect performance, presumably via lipid peroxidation in the liver.
Although a lot of food-derived peptides have been applied for medical use and therapeutic nutrition, the function of feed-derived peptides on nutritional physiology in chickens has not been clarified so far. Our previous study revealed that wheat gluten digested by trypsin could enhance the absorption of amino acids from small intestine. In the present study, we studied the influence of trypsin-digested wheat gluten peptides with different molecular weight (MW) on the intestinal absorption of amino acids in chickens. Wheat gluten was digested by trypsin and fractionated by using the ultrafiltration membrane. Wheat gluten peptides were divided into 3 fractions with different MW; MW more than 10,000, MW 3,000-10,000 and MW less than 3,000. Phosphate buffered saline and whole wheat gluten digesta were used as negative and positive controls, respectively. All of wheat gluten peptides were mixed with 2.5M glucose-10 mM amino acid solution and administrated into the crop with a stomach tube. At 20 min after oral administration, blood samples were taken from mesenteric vein. Plasma amino acid concentration was determined using an automatic amino acid analyzer. The peptide fraction with MW more than 10,000 increased the intestinal absorption of phenylalanine and proline. The peptide fraction with MW 3,000-10,000 increased the intestinal absorption of proline. These results suggest that wheat gluten peptide with high MW might have the potency to enhance the absorption of aromatic amino acids from small intestine of young chickens.
The skull of six Japanese fowl breeds, namely, Chabo, Oh-Shamo, Onagadori, Shokoku, Tosajidori, and Totenko, were morphologically compared in this study. The morphological differences in the skull size and shape among the breeds were as follows. 1) Oh-Shamo possessed a wide bill, thick bill tip, small orbits and wide mandibular joint. The characteristics of the bill and mandible were interpreted as functional characteristics to endure the shock of pecking. We suggest that the small orbits and a wide frontal bone help in protection from pecking in games. 2) Chabo possessed a small skull. In terms of shape, this breed possessed relatively large orbits, a wide and high skull and a short bill. The wide and high skull and the short bill formed a circular-shaped face. We propose that these characteristics have led to its characterisation as ornament-type fowl. 3) Totenko, Shokoku, Onagadori and Oh-Shamo possess a long mandible. The long mandible led to an increase in the volume of the oral cavity. The wide resonance space is responsible for the low-frequency voice. The low-frequency crowing of Totenko, Shokoku, Oh-Shamo and Onagadori is a result of the enlarged resonance space created by the long mandible. The orbits of Totenko and Onagadori were larger than those of Shokoku and Oh-Shamo. We suggest that Shokoku possessed the small orbits as a fighting cock. Since Onagadori and Totenko had been bred as ornament-type fowl, they possessed larger orbits.
Eggshell quality in birds results from mineral density and composition determining its mechanical endurance. The aim of the study was to determine interrelationships between morphological, densitometric and mechanical properties of eggs in Japanese quails. Twenty four eggs randomly collected from 17-week-old quails were subjected to morphological, denstiometric and mechanical evaluation using dual-energy X-ray absorptiometry (DEXA), quantitative computed tomography (QCT) and three-point bending test. Weight, height and width of eggs were positively correlated with the densitometric parameters obtained using DEXA (egg mineral density (EMD) and egg mineral content (EMC)) and QCT (total egg volume (TEvol) and total eggshell volume (TESvol)). Positive correlations were stated between TEvol and TESvol (r＝0.52; P<0.05) and EMD and EMC r＝0.83; P<0.05). Egg mineral density revealed positive correlations with TEvol and mean volumetric eggshell mineral density (MvESMD), while EMC was positively correlated with TEvol, TESvol and MvESMD (all P<0.05). Eggshell breaking strength was positively correlated with MvESMD (r＝0.53; P<0.05) and negatively correlated with eggshell thickness (r＝−0.50; P<0.05). In conclusion, the results obtained in this study showed numerous interrelationships between morphological, densitometric and mechanical properties of eggs in Japanese quails. Both DEXA and QCT were shown to be valuable tools for evaluation of whole egg and eggshell quality with superior prognostic value of QCT for eggshell mechanical endurance prediction. The elaborated experimental model may serve for further investigations on physiological, pharmacological, environmental, nutritional and toxicological factors influencing egg quality.
We evaluated the effects of caponization on mRNA levels of gonadotropin-releasing hormone-I (GnRH-I), gonadotropin subunit and other hypothalamic and hypophyseal peptide genes in male chicken. Thirty roosters (25 d) with similar weight were equally divided into the experimental (capons) and control (sham-operated males) groups randomly. Caponization was performed at 28 days of age and birds were slaughtered at 140 days of age. Caponization resulted in increasing levels of luteinizing hormone β (LHβ) and follicle-stimulating hormone β (FSHβ) mRNA in the pituitary gland and levels of LH and FSH in serum (P<0.05 or P<0.01). There were no significant differences in levels of GnRH-I, Gonadotropin releasing hormone receptor (GnRHR), neuropeptide Y (NPY) and Proopiomelanocortin (POMC) mRNA between the two groups. Capons exhibited lower levels of follistatin (FS), estrogen receptor α (ERα) and higher levels of androgen receptor (AR) mRNA in the pituitary gland compared with sham-operated males (P<0.05). These results suggest that increased LH and FSH concentrations in serum and LHβ and FSHβ mRNA levels in pituitary after castration are not depended on GnRH synthesis. And changed expression of ERα, AR and FS genes in the pituitary gland may be important components of regulating gonadotropin in capons.
Organisms measure day length to better adapt to seasonal changes in the environment; this phenomenon is called photoperiodism. The Japanese quail has a highly sophisticated photoperiodic mechanism and is an excellent model for the study of photoperiodism. Various lines of quail have been established during the domestication process. In the present study, we examined the effect of long day (LD) followed by short day (SD) on testicular weight in four lines of quail (L, AMRP, NIES-Br, and WE). When the quail were raised under SD conditions, testicular development was suppressed in all examined lines. The speed of the LD-induced testicular development of NIES-Br line was faster than that of AMRP line, while the speed of the SD-induced testicular regression of L line was significantly faster than that of WE line. These quail lines provide excellent model to uncover the underlying mechanism of seasonal testicular regression.
The PRL regulatory element-binding (PREB) protein is a transcription factor that was originally cloned from the rat anterior pituitary gland and characterized as a regulator of the PRL promoter. It is also strongly expressed in several extrapituitary tissues; however, its functional role is not well understood to date. In this study, we aimed to clone and characterize the turkey PREB gene and investigate its mRNA expression in the anterior pituitary gland and pancreas during embryogenesis. Based on the conserved sequence of chicken and mammalian PREB cDNAs, a turkey PREB cDNA fragment was obtained, and after sequencing of the fragment, the 5′- and 3′-ends of mRNA were amplified and determined. To identify the PREB gene structure, polymerase chain reaction (PCR) amplification was performed. The turkey PREB gene consists of 9 exons and 8 introns, and it encodes a 411-amino-acid protein. The expression of PREB mRNA in the anterior pituitary gland was measured during embryogenesis. Levels of PREB mRNA significantly increased at embryonic day 22, with maximum levels being detected on day 25 of ontogeny, which correlated with similar changes in levels of PRL mRNA. The highest level of PREB mRNA was detected on day 19 in the pancreas. However, the highest level of insulin mRNA was detected at embryonic day 25. These results indicate that PREB may be involved in the expression of PRL mRNA in the anterior pituitary gland, whereas insulin mRNA may be expressed independently of the expression of PREB mRNA in the pancreas during embryogenesis.
We evaluated the effects of different light-emitting diode (LED) colors between blue and green on growth performance and the immune response in broilers. A total of 1,200 1-day-old Ross broilers were divided randomly into six groups and exposed to pure blue (PB), bright blue (BB), sky blue (SB), greenish blue (GB), pure green (PG), or white (W) using LEDs for 6 weeks. Consequently, body weights were higher in chickens reared under PB and GB on day (d) 7 and SB on d 21 than the other groups. Chickens in the PB group on d 42 were the heaviest among the groups, followed by the BB group and were significantly heavier than the W group. Splenocyte proliferation was significantly enhanced in chickens reared under PB followed by BB on d 42 and proliferation of peripheral blood mononuclear cells was significantly enhanced in chickens reared under BB on d 42. In addition, chickens in the BB group showed significantly elevated nitric oxide production on d 42, indicating activation of macrophages. These results suggest that immune function and growth of broilers can be improved at the later stage by rearing under shorter wavelength LEDs such as PB and BB.
The effect of intracerebroventricular (i.c.v.) injection of a wide range of glucose concentrations on the behavioral response, central amino acid and monoamine contents was investigated in chicks exposed to a social isolation stressful condition. The chicks were given an i.c.v. injection of 0.21, 0.42, 0.84, and 1.68 μmol of D-glucose, and then behavioral changes were observed over 10 min. The behavioral stress response was dose-dependently decreased and calm behavior was increased by i.c.v. administration of glucose. In the diencephalon, glutamine was positively correlated, whereas glycine was negatively correlated with the dose of glucose. In the telencephalon, the dopamine metabolite and dopamine turnover rates were positively correlated, whereas dopamine was negatively correlated with doses of glucose. In the plasma, isoleucine and hydroxyproline were positively correlated with the dose of glucose, and several amino acids were also influenced by glucose levels. These results suggest that the possible pathways of the sedative effect of glucose include: (1) amino acids synthesized from injected glucose, which can induce the sedative and/or hypnotic effects; (2) amino acids modified by injected glucose transported in the brain from the peripheral tissues; and (3) injected glucose-induced decreases in brain dopamine levels. In conclusion, these changes induced by central glucose interact and induce the sedative effect in neonatal chicks.
This study aimed to characterize and optimize the tenderization condition of duck breast meat by adenosine 5′-monophosphate (AMP), with the aid of response surface methodology (RSM). The results showed that the optimal conditions for the tenderization of duck breast meat were at the NaCl concentration of 3.99 g/100 g, AMP concentration of 13.83 mmol/L, temperature of 15.32°C, and marinating time of 8 h. Compared with control duck breast meat, AMP combined with NaCl treatment demonstrated significant effects on improvement of meat tenderness and decrease of cooking loss. Such effects might be ascribed to the combination of a series of biochemical reactions, e.g. increase of muscle pH, dissociation of actomyosin and inhibition of meat shrinkage. Therefore, the mixture of AMP and NaCl could be regarded as an effective tenderization agent for duck breast meat.