케냐에서 토종 닭의 낮은 생산성은 부분적으로 열악한 관리 관행, 특히 적절한 건강 관리, 열악한 사육장 및 영양 부족 때문으로 알려져 있다. 이 연구의 목표는 케냐에서 산란계를 위한 신배합사료 배합 가능성 확인과 신배합사료 식 A와 B의 급이를 통한 계란 생산성을 분석하고자 하였다. 1. 2018년 7월 1일부터 2021년 3월 31일까지 Embu 및 Tharaka Nithi 카운티에서 닭 생산에 관심이 있는 농부 그룹을 선정하였다. 농부 그룹 선정에 사용 된 기준은 닭의 수, 닭 사육 및 장비에 대한 투자 수준, 사료 혼합에 대한 관심, 농가 집단의 응집력, 교육 수준 및 집단 구성원의 연령 등 이었다. 2. 총 3,968명의 농업인이 산란계를 위한 신배합사료 식 A와 B에 따른 사료조제 및 이용에 참여하였으며, 총 136,683 kg의 배합 사료를 조제하였다. Embu 지역에서는 2,774명의 농업인이 53,770 kg을, Tharaka Nithi 지역에서는 1,194명의 농업인이 41,313 kg의 신배합사료를 각각 조제하였다. 3. 신배합사료 식 A와 식 B가 케냐 표준 국 [KEBS] (2014)의 품질 표준을 충족하는지 평가하기 위해 사료 영양 성분을 분석한 결과, 신배합사료 식 A와 식 B, 상업용 사료 모 두 건물중(dry matter) 이 88%이상으로 표준을 충족 하였고, 최대 25% 이하의 회분(ash), 15% 이상의 조단백질(crude protein) 과 7.5% 이하의 조섬유(crude fiber) 기준과 대부분 부합하였다. 4. 신배합사료 식 A와 시판용 사료를 급여한 산란계 10마리의 일일 평균 계란 생산량을 비교한 결과 Embu 지역에서는 7.2개와 5.1개, 그리고 Tharaka Nithi 지역에서는 8.2개와 5.7 개로 유의적으로 높은 생산성 차이가 확인되었다. 5. 신배합사료 식 B와 시판용 사료를 급여한 산란계 10마리의 일일 평균 계란 생산량을 비교한 결과 Embu 지역에서는 7.3개와 4.9개, 그리고 Tharaka Nithi 지역에서는 7.1개와 5.2 개로 유의적으로 높은 생산성 차이가 확인되었다.

The present study evaluated the repellent activity and the improvements in egg production and mortality rate on laying hens infested with poultry red mites (PRM) administered with a mixture of Korean traditional herbal methanolic extracts (CHE, Foeniculum vulgare : Sophora flavescens : Cinnamomum cassia : Glycyrrhiza glabra = 1:1:1:1, w/w/w/w). PRM numbers per laying hens in CHE-0.5 administered with CHE 0.5 kg/ton feed were significantly decreased compared to those in Non-CHE (control) during overall experimental periods (1st week post-treatment, p<0.05; 2nd week post-treatment, p<0.01; 3rd-4th week post-treatment, p<0.001). In CHE-1.0 administered with CHE 1.0 kg/ton feed, PRM numbers were significantly decreased compared to those in Non-CHE during the whole experimental periods (1st week post-treatment, p<0.01; 2nd-4th week post-treatment, p<0.001). After administration of CHE for 4 weeks, egg production and mortality rate in CHE-0.5 and CHE-1.0 were significantly improved compared to those in Non-CHE (p<0.05). In addition, hematological and blood biochemical parameters in all CHE-treated groups were insignificantly different compared to those in Non-CHE. This study showed that CHE (0.5 and 1.0 kg/ton feed) had a repellent activity on PRM in laying hens and effects on the improvement in egg production and mortality rate of laying hen. CHE could be an effective and safe candidate for the control of PRM and the improvement in egg production and mortality rate of laying hens.

본 연구는 계란 생산성, 계란품질 및 악취저감에 관한 Bacillus subtillus, Streptomyces galilaeus 및 Sphingobacteriaceae로 구성된 복합생균제(PM, probiotic mixture)의 효과를 조사하였다. 산란계 Hy-Line Brown 240수를 4처리구로 구분하여 6주 동안 사육하였다. 처리구는 복합생균제를 함유하지 않은 대조구(CON, control), 일반생균제(CP3, commercial probiotics 0.3%), 복합생균제 3(PM3, 복합생균제 0.3%), 복합생균제 5(PM5, 복합생균제 0.5%)로 구분하였다. 산란율, 계란 호우유니트, 난각두께, 난각강도, 난황색 및 농후난백 높이는 PM3, PM5가 CON 및 CP3에 비해서 높았다. 계분으로부터 암모니아, E. coli, 총호기성균, Coliform, Salmonella 균수는 CON>CP3>PM3>PM5 순서로 증가하였다. 본 결과는 B. subtillus, S. galilaeus 및 Sphingobacteriaceae로 구성된 복합생균제 0.3%가 산란율, 계란품질 개선 및 분에서 암모니아 발생을 낮추어 양계장 악취저감 효과를 갖는다는 점을 보여 준다.

본 연구는 열 스트레스 (heat stress, HS)에 노출된 산란계에서 혼합 생균제의 급여가 생산성, 계란품질, 면역반응, 맹장 미생물 및 분 암모니아에 미치는 효과를 조사하였다. 총 400마리의 50주령 Hy-Line brown 산란계를 무작위로 각각 100마리씩 4 그룹, C (대조군, 실온 25℃), HS (열 스트레스 33℃), HSP (HS 플러스 혼합 생균제 500, 750 mg/kg)로 배치하였다. 산란계의 생산성, 계란품질, 비장 무게, 혈액 IgG 및 lymphocyte 농도는 HSP 그룹에서 HS 그룹과 비교했을 때 증가하였고, 코르티코스테론, heterophil과 lymphocyte의 비율 (H:L) 및 폐사율은 유의하게 낮았다. Lactobacillus는 HSP 그룹에서 HS 그룹과 비교했을 때 증가하였으나 Escherichiacoli (E. coli), coliform bacteria 및 aerobic bacteria는 유의하게 낮았다. 분에서 암모니아 발생은 HS 그룹이 HSP 그룹에 비해서 유의하게 증가하였다. 결론적으로, 이러한 혼합 생균제가 여름철 산란계의 더위 피해를 방해주고 면역반응, 맹장 미생물 균형을 경유하여 생산성, 계란품질 및 계분으로부터 악취 발생을 줄이는 데 효율적인 영양전략이 될 수 있음을 나타낸다.

The present study was conducted to determine the optimal supplementation level of beta-mannanase in the diet of laying hens. A total of 320 Hy-Line Brown layers (80 weeks of age) were assigned randomly into four groups on the basis of laying performance. Each treatment had eight replicates with 10 birds each (80 birds per treatment). Two hens were caged individually. Treatments were basal diet supplemented with 0 (control), 0.04, 0.08, and 0.16% beta-mannanase during the nine-week feeding period. Laying hens fed diets supplemented with increasing levels of beta-mannanase had increased (linear, p<0.05) overall egg production and egg mass. In addition, these hens had greater retention of dry matter, crude protein, gross energy, calcium, and mannan (linear, p<0.05). Dietary beta-mannanase treatments had no effect on blood metabolites such as total carbohydrate, triglycerides, glucose, total protein, and blood urea nitrogen, or excreted ammonia nitrogen and volatile fatty acids. The results obtained in present study indicate that dietary supplementation of beta-mannanase has the potential for improving the performance of laying hens. The optimal supplementation level is 0.04% beta-mannanase in the diet.

The insulin-like growth factor binding proteins (IGFBPs) is involved in the regulating effects and the biological activities of the insulin-like growth factors (IGFs). Recently, It has been reported that the IGFBP2 gene polymorphism was associated growth and skeletal development in chicken. This study was designed to investigate the association of the C1032T SNP of IGFBP2 gene with growth and egg production traits in Korean native chicken (KNC) population as well as other chicken breeds. A total of 225 chickens from the three breeds (Rhode Island Red, Cornish, Leghorn) and 245 chickens from the six strains of Korean native chickens including Black, Gray, Ogol, Red, White, and Yellow, were genotyped by PCR-RFLP (polymerase chain reaction-restricted fragment length polymorphism) and analyzed the association between their genotypes and economic traits by SAS program. The results showed that the SNP (single nucleotide polymorphism) was significantly associated with multiple traits, including body weight of 150 days (p<0.001 and p<0.05) in the Rhode Island Red and the KNC (White) and egg production number (p<0.05) in the KNC (Black) breed. These results suggest that IGFBP2 C1032T SNP could be used as a DNA marker for the improvement of economic traits in Korean native chicken breeding.

Single nucleotide polymorphisms (SNPs), that usually occurs with a modification in single nucleotide among the population of 1000 nucleotides. Such changes in nucleotides have been investigated and been associated by meat scientist for economically important traits and to increase economical profits in stock breeding. Pluralities in the study have correlated SNPs of potential candidate gene with economically important traits in domestic animals have been put forward. In chickens, INS, IGF1, IGF1R, IGFBP, CAPN1, CAPN3, GHSR, FATP1, FGFBP1, FGFBP2, apoVlDL-Ⅱ, PB1, miR-1614-3p, DAAM1, Wnt3A, LRP5, CHP, RHOA, MAPK9, SFRP1, ATGL, PGC-1α, NPY, GnRHR, PRL, TGFβ2, CASR. UCP, ADSL, STAT5b, LRP2 and CTSD genes have been found to have significant effects on body weight, breast muscle weight, carcass weight and egg number. For the similar reasons, SNPs of these genes have been considered useful DNA markers for the improvement economic value of poultry. Although further studies on different breeds of chickens would be required to segregate such dataset for different breeds of chickens.

Antibodies are used for preventing several infectious diseases in food animals. Though, antibiotics can deal with infection however, their widespread usage may cause developments of resistance and can also get transferred to humans through animal products. Therefore, production of antibodies against infectious agents in the egg yolk could be an interesting alternative. The present study was conducted with a focus on producing the antibody against Escherichia coli E68 and H28 in egg yolk of laying hens, which are believed to be a cause for diarrhea and beriberi in piglets. The result received from the experiment were promising and have shown efficiency of antibody production in the range of 2-7.3% in the groups which are infected with E68 only and the one which was infected with both strains. The outcome of present research has revealed the potentiality of egg yolk in production of antibody for laying hens, could open a new approach for production of antibodies to manage diarrhea and beriberi

This study was conducted to evaluate the feeding value of black soldier fly pupa (BSFP) on fecal microorganism, immunoglobulinm egg quality and egg production laying hens. One hundred twenty laying hens were assigned to 4 treatments (0, 5, 7 and 10% BSFP) with 3 replicates for 8 weeks. The formulae of 4 experimental diets were modified to contain 18% CP and 2,900 kcal/kg. All the treated groups differed in feed intake, egg production, egg weight and egg mass compared to those of a control group. The egg weight and production were increased (p < 0.05) in BSFP groups compared to the control. The HDL-C was increased (p < 0.05) in BSFP groups compared to the control. The level of immunoglobulin IgG and Haugh unit were increased (p < 0.05) in BSFP groups compared to the control. These result suggested that the addition of BSFP to the layer diet could improve the egg quality and the laying performance.

This study aimed to evaluate the effects of dietary microbial-fermented molasses on egg production and egg quality in laying hens.In total, 90 Hy-line Brown laying hens were divided into two treatment groups (control and 1% microbial-fermented molasses)with three replicates of 15 birds each. During the experimental period, supplementation of hen diets with 1% microbial-fermented molassesdid not influence egg weight, hen-day egg production, egg mass, and feed conversion ratio (p > 0.05), except for feed intake. Regarding egg quality, diets containing 1% microbial-fermented molasses significantly affected eggshell thickness, Haugh unit, and albumen height (p < 0.05). However, there were no remarkable differences between control and 1% microbial-fermented molasses in eggshell color and egg yolk color (p > 0.05). These results indicate that supplementing 1% microbial-fermented molasses to the diet of laying hens improved egg quality parameters such as eggshell thickness, Haugh unit, and albumen height rather than egg production.

As a preliminary investigation into the effect of environmental factors control for gonadal development, we examined the involvement of photoperiod and water temperature in ovarian development of Epinephelus. akaara. For the induction of sexual maturation, E. akaara reared in recirculating aquaculture system (RAS). During November 2013, the photoperiod and water temperature was adjusted to 12L:12D and 18℃, respectively. In the photo-thermal treatment group, every 3 weeks daylight was increased as follows a 13L:11D and 14L:10D, and control group was maintained under natural condition. After 9 weeks, water temperature was increased 23℃ in photo-thermal treatment group. The sampled fish every 3 weeks revealed increase in gonadosomatic index (GSI; 5.18±1.38), oocyte diameter and vitellogenic oocytes (423.9±36.1 ㎛) were observed in gonads 12 weeks under photo-thermal treatment group. However, ovarian development was maintained immature stage in control group. In this environmental factors manipulation trial, seventy one of the 95 females (578.4 ± 25.4 g in mean body weight, 31.0 ± 0.5 cm mean total length) treated with HCG injection (doses 500 IU/kg BW) were induced ovulation by artificial stripping. The total volume of ovulated eggs were 3,470 ml and the total volume of fertilized eggs was 3,295 ml. The fertilization rate and hatching rate were 95% and 98%, respectively. These results suggest that the photoperiod as well as water temperature are major environmental factors in triggering the gonadal development of E. akaara.