In this paper, we consider the ethics of poultry production from different perspectives, applying both intrinsic and extrinsic ethical principles. We consider the perspectives of the animal, farmer, consumer, breeders, researchers, and policy-makers. Intrinsic ethical factors include feeling pain and experiencing suffering, self-awareness and consciousness, future planning ability, the value of being alive, and individual love of life. Extrinsic factors include human necessity and/or desire, human sensitivity to animal suffering, fear of causing brutality in humans, disapproval of other animals, and the religious status of animals. The development of systems to create more ethical poultry production systems is a work in progress, and in the evolution of ethical standards, moral progress and what can be described as more ethical poultry are evident.

The Japanese quail expresses polymorphism in plumage colors, including black, yellow, white, wild-type (maroon), and various intermediate colors through hybridization of quail with different plumage colors. The expression levels of MC1R and ASIP play important roles in the regulation of plumage colors in birds. In this study, the eukaryotic expression vector of pcDNA 3.1 + was used to analyze the effects of forced expression of MC1R and ASIP on the plumage colors of Japanese quail embryos. The constructed eukaryotic expression vectors of pcDNA 3.1 (+)-MC1R and pcDNA 3.1(+)-ASIP were transfected into wild-type Japanese quail embryos by Lipofectamine™ 2000 liposome at 6 days of incubation. After 3 days, the embryos were collected to analyze the plumage colors and the expression levels of MC1R, ASIP, and DCT genes in skin tissue. Forced expression of the MC1R gene by transfection of the pcDNA 3.1(+)-MC1R vector led to hyperpigmentation (similar to black plumage), whereas forced expression of the ASIP gene by transfection of the pcDNA 3.1(+)-ASIP vector led to hypopigmentation (similar to white plumage) in wild-type quail embryos. Two kinds of ASIP alternative splicing (ASIP1 and ASIP2) were found in Japanese quail, which did not have a significant effect on the plumage color or the main motifs of the ASIP protein. This study indicated that the black plumage color may be caused by increased production of MC1R and the white plumage color may be caused by increased production of ASIP in Japanese quail.

Amakusa Daioh cross chickens are F₁ hybrids of restored Amakusa Daioh sires and Kyushu Rhode dams. In the present study, the association between a single nucleotide polymorphism (SNP; AB604331, g.420 C>A) in the cholecystokinin type A receptor gene and growth traits in Amakusa Daioh cross chicken were investigated. We used 72 male and 72 female birds that had hatched on the same day, were raised in the same chicken house, and were fed the same diet ad libitum from day 0 to 17 weeks (wks) of age. Body weight was recorded at weekly intervals and average daily gain of each week interval was calculated from body weight data. Birds were sacrificed at 17 wks and carcass traits were recorded. SNP genotyping was carried out using the mismatch amplification mutation assay. Associations between the SNP and growth traits were analyzed by a generalized linear model. Body weight from 6 to 17 wks was higher in birds with the A allele than in birds with the C allele, although significant differences in average daily gain traits between birds with A and C alleles were not detected during most of the duration of the experiment. Carcass data showed that birds with the A allele had heavier wings and a smaller proportion of the gizzard than those with the C allele. The g.420 C>A SNP will be useful as a selection marker for parent stock lines to increase the growth performance of Amakusa Daioh cross chickens.

The Miyazaki Jitokko chicken, native to the Miyazaki Prefecture in southern Kyushu Island, Japan, is the product of a three-way cross involving the Jitokko, White Plymouth Rock, and Kyushu Rhode breeds. In the present study, associations between a single nucleotide polymorphism (SNP; AB604331, g.420 C>A) of the chicken cholecystokinin type A receptor gene and growth traits in Miyazaki Jitokko chickens were investigated. Unrelated male birds (n=120) that had hatched on the same day were raised in the same chicken house and fed the same diet ad libitum from day 0 to 17 weeks of age. Body weight was recorded at 0, 1, 2, 3, 4, 5, 7, 9, 11, 13, 15, and 17 weeks and the average daily gain of each interval was calculated from the body weight data. SNP genotyping of each bird was performed using the mismatch amplification mutation assay. The associations between the SNP and growth traits were examined using the Thesias program. The genotype frequencies of AA, AC, and CC were 0.525, 0.383, and 0.092, respectively. AA birds were significantly heavier than CC birds from 4 to 17 weeks of age. In the estimated effect of alleles, body weight from 1 to 17 weeks of age in birds with the A allele was greater than that in birds with the C allele. During the rearing period, the effect of the A allele on average daily gain in the first half was greater than that in the second half. We conclude that the g.420 C>A SNP can be used as a selection marker for the parent stock lines of the Miyazaki Jitokko chickens to increase their growth performance.

Excessive fat deposition adversely affects poultry production. In this study, we investigated growth, fat deposition, and hepatic mRNA expression of 13 lipid metabolism-related genes in three unique breeds of meat-type chickens with distinct breed origins and genetic relationships. One was Nagoya (NAG), a native Japanese breed, whereas the others were White Plymouth Rock (WPR) and White Cornish (WC), which have been used worldwide as the parental breeds of common broiler chickens. NAG chickens were phenotypically characterized by slow growth, lean body fat, and high gizzard and liver weights. In contrast, both WC and WPR chickens were characterized by rapid growth but high percentage of subcutaneous fat and abdominal fat weight, resulting from high feed intake. Among the three breeds, WC had the highest percentage of pectoral muscle weight, whereas WPR was the most obese. Among lipid metabolism-related genes, the expression of PPARA, PPARG, and CD36 was mostly associated with obesity. These results provide basic information for quantitative trait locus (QTL) analysis related to growth and fat traits in an F₂ population of the lean NAG breed and the obese WPR breed of meat-type chickens in future.

The growth performance, nutrient digestibility, hematology, serum chemistry, and lipoprotein concentrations of turkey (Meleagris gallopavo) poults fed diets supplemented with high or recommended concentrations of niacin were investigated in this study. A total of 120 four-week-old turkey poults were randomly divided into three treatment groups with five replicates of eight birds in each group. The poult diets were supplemented with 0.0, 60, and 180 mg/kg niacin in the three treatments, termed control, recommended niacin supplementation (RNS), and high niacin supplementation (HNS), respectively. The study lasted for four weeks. The results showed that the HNS treatment reduced the feed intake and increased the body weight gain of poults. The apparent, nitrogen-corrected, and true metabolizable energy contents were the highest in the HNS-group turkey poults (P<0.05). The red and white blood cell counts and hemoglobin concentration of the turkeys improved with increasing niacin supplementation (P<0.01). The serum constituents, including the serum protein and globulin, were significantly increased (P<0.05), while the uric acid and creatinine contents were significantly reduced in the HNS-group turkeys. Similarly, the HNS-group turkeys exhibited significantly reduced alanine aminotransferase (ALT) and alkaline phosphatase (ALP) contents, while the RNS-group turkeys had the least aspartate aminotransferase (AST) content. In addition, the HNS-group turkeys had the least serum low-density lipoprotein (LDL), triglyceride, and total cholesterol concentrations and the highest serum high-density lipoprotein (HDL) (P<0.01) concentrations. In conclusion, the supplementation of 180 mg/kg niacin in the diet reduced the feed intake and serum ALT, ALP, LDL, triglyceride, and cholesterol contents and increased the body weight gain, metabolizable energy, and HDL concentration in turkeys. This study showed that niacin supplementation could reduce the fat content without compromising the body weight gain and increase stress resistance in turkey poults.

This study was performed to investigate and compare the effects of using Artemisia annua leaves, probiotic, and organic acid on the performance, egg quality, blood biochemistry, and antioxidant status of laying hens. In total, 288 Hy-Line W-36 commercial layers (32 weeks old) were divided into six groups with six replicates per group (eight birds per replicate) and were fed one of six experimental diets. The hens were fed either a corn-soybean meal basal diet (control) or the basal diet supplemented with 2.5% A. annua leaves (AA1), 5% A. annua leaves (AA2), 7.5% A. annua leaves (AA3), 0.1% probiotic (Pro), and 0.005% organic acid (Org), respectively. The experiment lasted 10 weeks. Results showed that there were differences in the feed conversion ratio (FCR) among experimental groups (P<0.05). The highest yolk color index and shell thickness were observed in hens fed AA3 and AA2 diets (P<0.05). Egg yolk cholesterol was decreased (P<0.01) by the diet containing AA3 and Pro compared to the other groups. The atherogenic index was lower (P<0.01) in the plasma of hens fed AA3 than those in other groups. The glutathione peroxidase activity (GSH-Px) and malondialdehyde (MDA) contents in layers fed AA3 were lower and higher (P<0.05), respectively, than in layers fed the other diets. Moreover, the concentration of plasma cholesterol was decreased (P<0.05) in layers fed AA3 and Pro. In conclusion, feeding laying hens with A. annua leaves positively influenced the plasma antioxidant status, and the dietary inclusion of A. annua leaves plus a probiotic significantly decreased the egg yolk cholesterol, with no adverse effect on the egg productive traits.

Cordyceps militaris is a well-known Chinese medicinal fungus that has been used as a nutraceutical food in several Asian countries. Cordycepin (3′-deoxyadenosine), a secondary metabolite produced from Cordyceps militaris, has been demonstrated to exert a wide spectrum of pharmacological activities, such as anti-microbial and antitumor activities. However, the effect of cordycepin on immunomodulation in broilers is poorly investigated. In the current study, we investigated the effect of cordycepin (9.69, 19.38, and 38.76 mg) from Cordyceps militaris hot water extract (CMHW) on growth performance and immunocompetence in broilers. Results showed that CMHW significantly decreased inducible nitric oxide synthase (iNOS) mRNA levels in the bursa of Fabricius after 4 weeks of feeding (P<0.05). CMHW treatment reduced cyclooxygenase-2 (COX-2) mRNA levels in the spleen and bursa of Fabricius after 4 weeks of feeding (P<0.05). Supplementation of CMHW for 3 days after vaccination reduced iNOS mRNA level in the spleen of 14 and 28 day-old broilers (P<0.05). Prior to vaccination, CMHW pretreatment significantly down-regulated COX-2 mRNA levels in the spleen and bursa of Fabricius of 14-day-old broilers (P<0.05). Furthermore, CMHW significantly reduced lipopolysaccharide (LPS)-induced iNOS and COX-2 mRNA levels in the spleen and bursa of Fabricius (P<0.05). CMHW treatment attenuated LPS-induced IFN-γ expression in the spleen and bursa of Fabricius, whereas CMHW induced IL-4 expression in these organs in response to LPS challenge (P<0.05). Taken together, these observations demonstrate that CMHW exerts an immunomodulatory role in broilers. CMHW is a potential novel feed additive with applications in inflammation-related diseases and bacterial infection in broilers.

This study aimed to evaluate the effect of dietary supplementation of a mixed yeast culture (MYC; Saccharomyces cerevisiae YJM1592 and Kluyveromyces maxianus TB7258 in a 1:1 ratio) on growth performance, nutrient digestibility, meat quality, blood parameters, and gut health of broiler chickens. In total, 576 one-day-old male broilers (Ross 308) with an average initial bodyweight (BW) of 37±0.51 g were used in a 35-day experiment with a completely randomized design. The broilers were randomly assigned to 3 dietary treatments: CON, basal diet; TRT1, CON + 0.1% MYC; and TRT 2, CON + 0.2% MYC. From days 8 to 21, the feed conversion rate (FCR) was significantly decreased in broilers fed MYC-supplemented diets. From days 22 to 35, BW gain (BWG) significantly increased with increasing MYC concentration. Throughout the experiment, BWG increased (linear effect, P=0.002) and FCR decreased with increasing MYC in the diet. MYC supplementation increased the digestibility of dry matter (DM) in broilers in a dose-dependent manner. Relative organ weight of the bursa of Fabricius linearly increased in broilers fed MYC-supplemented diets. The white blood cell count showed linear and quadratic increases in broilers fed increasing concentrations of MYC. The population of Lactobacillus in the excreta linearly increased P=0.033, whereas that of Escherichia coli tended to linearly decrease (P=0.064) in the MYC groups. This study provides a basis for future research on MYC as a growth promoter in broilers.

Higher light wavelengths have been shown to stimulate extra-retinal photoreceptors more efficiently than lower wavelengths to promote reproduction in poultry. We developed a light emitting diode (LED) bulb that emits 60% of its light in the red spectrum (LED-R), and evaluated the effects of different light sources on growth and reproduction in commercial layer hens. Three rooms equipped with either 100W incandescent, 15W compact fluorescent (CFL), or 10W LED-R bulbs were populated with 96 Lohmann LSL-Lite layers housed in individual cages from 14 to 69 weeks of age (woa). Pullets were initially maintained on a 10-h photoperiod, then photostimulated at 18 woa. Surprisingly, regardless of the light source, plasma levels of estradiol peaked at 16 woa, 2 weeks before photostimulation, and egg-laying was initiated at 19 woa. As a direct correlation between age at first egg and body weight was identified, metabolic cues most likely served as a primary trigger to initiate sexual maturation prior to photostimulation. Overall egg production and cumulative egg numbers were similar among treatments. Interestingly, a second increase in estradiol was observed at 52 woa under all treatments, suggesting an additional ovarian stimulation, possibly associated with an additional follicular recruitment at that age. Overall, changes in estradiol concentrations were more pronounced in hens maintained under LED-R light than in hens exposed to incandescent and CFL, especially for the second increase, suggesting that a higher amount of red light leads to stronger ovarian activity. Maintaining hens under LED-R bulbs also resulted in lower feed consumption, which combined with the lower energy consumption of LED-bulbs (LED-R: 306 kW; incandescent: 2,514 kW; CFL: 422 kW) could reduce the production cost.