Egg Yield Research Articles

Эффективность влияния пребиотической кормовой добавки на продуктивность, антиоксидантную защиту и иммунологический статус кур

Purpose. The study of the productive traits of chickens when fed with a prebiotic supplement that stimulates the antioxidant and immunological defenses of the body Materials and Methods. The studies were carried out in certified laboratories. The resulting digital material was processed using the statistical package Microsoft Excel, which provides verification of the reliability of the data using the Student's criterion. Results. It has been established that the introduction of the feed additive "LactuSuper" into the diet of laying hens of the Hisex Brown cross dramatically increases their productivity by 85 eggs in 10 weeks of the experiment, or by 1.2 eggs per positive laying hen, the egg-laying intensity – by 1.74%, feed savings – by 0.6 g per day per head, obtaining a hatching egg yield of 4% (97% compared to 93% of the control group). The balance of the feed additive "LactuSuper" with biologically active absorbed absorbable carotenoids in the yolk of the incubation eggs of the experimental group was 23.36% (P≤0.001), which was 16.9 µg/g in absolute values. Incubation of eggs showed a high hatch of chickens in both groups (82.44 and 85.27%), but in the experimental group, the excess in this indicator was 2.83%. High rates of production and quality of hatching eggs in the experimental group, apparently, are provided by the activation of metabolism in the body of chickens, as a result of feeding them the studied additive. Due to the antioxidant properties of the tested feed additive the activity of superoxide dismutase (SOD) increased by 11.22% (P≤0.01), glutathione peroxidase (GPO) – by 3.02% (P≤0.05), ceruloplasmin (CP) – by 16.58% (P≤0.01), total antioxidants (TOA) by 26.97% (P≤0.01), and malondialdehyde (MDA) activity decreased by 14.15% (P≤0,01). The level of T-lymphocytes responsible for cellular immunity increased by 12.61% (P≤0.01), and the content of B-lymphocytes characterizing humoral resistance increased by 6.83% (P≤0.05) relative to the control. An increase in the level of classical antibodies was recorded in the experimental group. Thus, the content of IgA and IgG increased by 17.26 (P≤0.01) and 7.62% (P≤0.05) compared with the control. The presence of IgM also exceeded the control values in the experimental group by 7.79% (P≤0.05). Conclusion. Thus, it was found that the feed additive "LactuSuper" developed by us contributed to the increase in the egg production of the parent flock and the quality of hatching eggs. The active substances of the prebiotic supplement ensured a decrease in the level of free radical lipid oxidation, which had a positive effect on the formation of the body's antioxidant defense, strengthening cellular and humoral immunity.

Chickens feed resources and feeding trends in Konso Zone and Derashe special district, Southern Ethiopia

The study was conducted to assess locally available chicken feed resources and feeding trends in the Karat zuria district of the Konso zone and Derashe special district. Multi-stage sampling techniques were used and a total of 120 respondent farmers from the districts who possess chicken production were involved. The data were collected by questionnaire, personal observation, and interviews. Potential cereals: sorghum (95.0±0.22% and 86.7±0.34%), teff (65±0.48% and 66.7±0.48%) from pulses haricot bean (58.3±0.50% and 45.0±0.50%); as vegetables Moringa stenopetala locally: Halako (96.7±0.18 and 91.7±0.28) in Karat zuria and Derashe special districts, respectively were identified as commonly locally promising human food as well as chicken feeds. Cooked food scraps (Fosase, Kurkufa); kitchen wastes, and protein sources (growing worms, termites, insects, grasshoppers, flies) local brewery residues (Cheka residues) were highly ranked as potential scavengeable feed resources (SFR) in both districts. However, January to May is the major month of the year severity of feed shortage (90% of respondents) mostly occurred. About 2/3 of farmers spreading the grain on the bare ground together for the whole groups of chicken once per day mainly for egg yield (41.67% of respondents) in the area was a very common trend of providing supplementary feed. Consequently, efforts have to be made to design and implement interventions, aiming at improving chicken feed resource base and feeding trends.

Associations of polymorphisms in prolactin and dopamine receptor D2 genes with reproductive traits on Silkie chicken

The Silkie chicken (Gallus gallus domesticus Brisson) is one of domestic chicken breeds with commercial rearing and breeding potentials for egg production. Prolactin (PRL) and dopamine D2 receptor (DRD2) are potential genes associated with reproductive traits in chickens. This study was conducted to analyze the association of PRL and DRD2 insertion/deletion (Indel) polymorphisms with chicken reproductive traits in Silkie chickens. A total of 380 hens from 16-40 weeks of age were used, with each one being placed in a separate cage. DNA isolation was performed using feather samples, and genotypes were detected using the Indel technique. Two polymorphisms consisting of 24 base pair (bp) Indel in the promoter region of the PRL gene and 22 bp Indel in the promoter region of the DRD2 gene were identified. At both sites, the Indel polymorphisms did not follow the Hardy-Weinberg equilibrium. In addition, with the exception of total eggs over 23 weeks of laying in the PRL gene, the analysis revealed no association between these polymorphic loci and any traits collected. In conclusion, birds with the DD genotype produced the maximum egg yield (73.6 eggs/hen), whereas those with the II genotype produced approximately 9 fewer eggs (64.1 eggs/hen), resulting in laying rates of 45.7% and 40.1%, respectively. For enhancing the egg-laying capacity of Silkie chickens via selective breeding, opting for DD birds with DD genotype of PRL Indel is highly recommended.

Quality control applications for recovering an inbred colony of Bagrada hilaris (Hemiptera: Pentatomidae).

The invasive stink bug, Bagrada hilaris (Burmeister), recently became established in the southwestern United States and has become a major pest of broccoli and other cole crops. Due to concerns about its possible establishment in Florida, a colony of this pest was maintained in quarantine to conduct research on its environmental requirements. The colony was reared reliably with approximately 300 adults per generation but began to decline in generation 16. Due to unknown causes, only about 73 females were recovered to mate and oviposit during the final 46 days. However, a corresponding decrease in the number of mated pairs did not reduce the yield of eggs, nymphs, and adults per day, but the females were maintained for fewer than the normal 160 days per generation. Therefore, quality control procedures were implemented to increase the number of days the colony produced adults in subsequent generations. The goal of producing approximately 400 adults per generation was accomplished during 104, 160, and 156 days, respectively, in generations 17, 18, and 19. The purpose of this research was to develop quality control procedures for rearing B. hilaris, use the procedures to restore a colony in quarantine, and describe how quality control can be used to maintain small colonies of insects. Implementing quality control procedures when a colony is established can help to prevent its decline.

Pectoral angle: a glance at a traditional phenotypic trait in chickens from a new perspective

AbstractIn meat-type poultry breeding, pectoral angle (PA) is a conventional anatomical indicator for changes in body conformation and meat traits; its correlation to egg performance is however deemed controversial. In this context, we revisited, assessed and put forward evidence for the usefulness of this classic phenotypic variable and its specific integrative index of pectoral angle-to-body weight ratio (PA/BW). Specifically, we identified respective correlations and used them for distinguishing the major categories (production types) of diverse chicken breeds under the traditional classification model (TCM) and genotypic clustering models of the global chicken gene pool subdivision. Also, the usefulness of the supplementary integrative egg mass yield index (EMY) for this objective was demonstrated. Because of estimating the total mass of eggs laid (i.e. egg number times egg weight), EMY can serve as an indicator of egg production. Direct approximation of EMY values by PA and BW values did not lead to significant correlation dependences between these indicators in each of the four breed utility types according to TCM. However, using the ratio of PA to BW, instead of PA and BW alone, resulted in significant correlation of EMY with PA/BW, allowing for distinction between egg-type and non-productive breeds. The validity of the proposed correlation-based models was supported by PCA and Neighbor Joining clustering analyses. Collectively, we suggested that PA can be a potentially correlated trait for selecting hens and roosters in breeding flocks to boost egg yield. These results can also be applied to chicken breeding as well as conservation- and phenome-related research.

Detection of Soil Transmitted Helminths (STH) Eggs Using Nail Test and Stool Test Among Scavengers at Jatibarang Landfill Semarang

<p><em>Helminthiasis or worm infection is caused by worm parasites belonging to Soil Transmitted Helminths (STH) group. Helminthiasis in human often occurs due to environmental factors and personal hygiene issue. The gold standard diagnosis of helminthiasis is done by identifying the worm eggs in the feces or stool. Based on its transmission, helminthiasis examination can be done by observing the nails. This study analyzed the prevalence of helminthiasis in nails and stool and examined the differences in the yield of helminth eggs between nail and stool. A simple random sampling technique was conducted to select 50 scavengers at Jatibarang Landfill, Semarang. Univariate analysis was used as data analysis tool to determine the prevalence of worm infections, while bivariate analysis in the form of Mann Whitney differential test was employed to determine the gap in the number of Soil Transmitted Helminth (STH) worm eggs in nail and feces samples. Ascaris lumbricoides worm eggs appear dominated the infections, with infection rates through nail of 2% and feces of 12%. p = 0.049 (<0.05) was obtained in the Mann Whitney test, indicating the presence of significant difference and implying that nail test cannot replace stool test as the gold standard of helminthiasis diagnosis.</em></p>

Beneficial impacts of biochar as a potential feed additive in animal husbandry

In the last decade, biochar production and use have grown in popularity. Biochar is comparable to charcoal and activated charcoal because it is a pyrogenic carbonaceous matter made by pyrolyzing organic carbon-rich materials. There is a lack of research into the effects of adding biochar to animal feed. Based on the reviewed literature, including its impact on the adsorption of toxins, blood biochemistry, feed conversion rate, digestion, meat quality, and greenhouse gas emissions, adding biochar to the diet of farm animals is a good idea. This study compiles the most important research on biochar's potential as a supplement to the diets of ruminants (including cows and goats), swine, poultry, and aquatic organisms like fish. Biochar supplementation improves animal growth, haematological profiles, meat, milk and egg yield, resistance to illnesses (especially gut pathogenic bacteria), and reduced ruminant methane emission. Biochar's strong sorption capacity also helps efficiently remove contaminants and poisons from the animals' bodies and the farm surroundings where they are raised. Animal farmers are predicted to make greater use of biochar in the future. Biochar could potentially be of value in the healthcare and human health fields; hence research into this area is encouraged. The present review highlights the potential benefits of biochar as an additive to animal feed and demonstrates how, when combined with other environmentally friendly practices, biochar feeding can extend the longevity of animal husbandry.

The effects of different choice feeding methods on laying hen performance, egg quality, and profitability

This study was conducted to investigate the effects of using whole wheat in choice feeding on performance, egg quality, and income of laying hens. In the study, a total of 160-Hyline W-80 white commercial laying hens aged 28 weeks were divided into four treatment groups and fed for 84 days. The treatment groups were as follows: 1) Control (C, standard commercial laying hen feed), 2) C feed+choice feeding continuously with whole wheat in a separate cup (CW), 3) C feed+weekly intermittent choice feeding with whole wheat in a separate cup (WW), 4) C feed+choice feeding with continuous whole wheat+limestone together in a separate cup (WL). Choice feeding by using whole wheat methods (continuous, weekly intermittent, and with limestone) caused a significant decrease in the live weight change of laying hens (P<0.01), increased feed consumption, and feed conversion ratio compared to the control group (P<0.05). Total egg yield and egg weight were not affected by choice feeding with whole wheat methods (P>0.05). Choice feeding by using whole wheat caused a decrease in total eggshell weight, thickness, shell weight per unit area, and egg yolk color (P<0.01). However, it did not significantly affect the egg shell ratio, surface area, albumen height, and Haugh unit values of eggs (P>0.05). Also, total production costs, egg sales income, and net profit values were similar in all groups (P>0.05). In conclusion, the choice feeding by using whole wheat in laying hens did not affect the performance and economic parameters negatively; however, it caused reductions in some egg quality values.

Knockout of tyramine receptor 1 results in a decrease of oviposition, mating, and sex pheromone biosynthesis in female Plutella xylostella.

Mating and oviposition are essential and closely coordinated events in the reproduction of moths. Although tyramine, a biogenic amine, can affect insect reproduction by binding its receptors, the specific regulatory mechanism has not yet been fully elucidated. Plutella xylostella mutant with tyramine receptor 1 (TAR1) knockout (homozygous mutant with 7-bp deletion, Mut7) was developed by the CRISPR/Cas9 system to investigate the effect of TAR1 knockout on the reproduction of the moth. Compared with wild-type (WT), the egg yield of Mut7 female (Mut7F ) was significantly lower, no significant difference was observed in the egg size and hatching ratio between the groups. Further analysis showed that TAR1 knockout adversely affected ovary development, characterized by shorter ovarioles and fewer mature oocyte. Additionally, TAR1 knockout significantly reduced the occurrence of mating, resulting in a decrease in egg yield in Mut7F . The amounts of sex pheromones were quantified using gas chromatography-mass spectrometry. Results showed that the amounts of sex pheromone released by Mut7F were significantly lower before mating. Correspondingly, the messenger RNA (mRNA) levels of sex pheromone biosynthesis enzymes, including acetyl-CoA carboxylase (ACC) and desaturase (DES), were significantly lower in the Mut7F pheromone gland. The decreased sex pheromone biosynthesis in Mut7F , especially before re-mating, may be related to the underexpression of pheromone biosynthesis-activated neuropeptide (PBAN). Overall, this study investigated the effect of PxTAR1 on oviposition and mating of P. xylostella. We report for the first time that TAR1 knockout could reduce the sex pheromone biosynthesis. These findings provide insights for developing a novel integrated pest control strategy based on mating interference. © 2023 Society of Chemical Industry.

Kuluçkahane Kökenli F5 ve F6 Nesil Karadeniz Somonu Anaçlarının (Salmo labrax PALLAS, 1811) Üreme Performansları

In this study, reproductive performances of F5 and F6 generation hatchery-originated female Black Sea salmon (Salmo labrax) were evaluated to determine the effects of the ongoing selective breeding program. The study was conducted in freshwater pools and marine cage systems between 2018 and 2021. For the study, 53 specimens from F5 generation females with an average length of 52.71±7.08 cm and weight of 1561.29±639.76 gr, and also 56 broodstıcks specimens from F6 generation females with an average length of 51.92±5.35 cm and weight of 1506.12±417.28 gr were used. Gonad maturity controls and spawning studies were carried out in the 2018-2019, 2019-2020 and 2020-2021 breeding periods along the entire season, lasting from November to January. The number of ovulating females, their fecundity, egg diameters and fertilisation rates of eggs were recorded. In all seasons, 36.17% of F5 females ovulated in November, and the remaining females (63.83%) ovulated in December. Ovulation time in F6 females also showed a similar pattern of 1/3 of females (37.40%) ovulating in November and the remaining majority (62.60%) ovulating in December. According to the results, total egg yields as 4439.31±1675.69 and 4112.08±1041.16 egg/broodstock, relative egg yields as 2313.44±278.48 and 2345.76±516.30 egg/kg, egg diameters as 5.08±0.19 and 5.21±0.17 mm, and fertilisation rates as 96.78±3.24% and 96.63±3.73% were determined for F5 and F6 generations, respectively. In both generations, as the size of the broodstock increases, the total egg production increases (F5: r=0.9169, F6: r=0.74254), while the relative egg production (F5: r=-0.2526, F6: r=-0.3486) decreases. When the total egg yields and fertilisation rates were compared, the difference between the F5 and F6 groups was insignificant (p≤0.05). The condition factors of the two generations were found to be statistically similar (p≤0.05).

BROODING PRACTICES OF LOCAL CHICKEN PRODUCERS AND ON-STATION EVALUATION OF NOVEL BROOD NEST ON HATCHABILITY OF CHICKEN EGG AT GAMO ZONE, SNNPR, ETHIOPIA

A survey was conducted at Gamo Zone of SNNPR, Ethiopia, to assess the indigenous practices of incubation, brooding, egg selection practices, broody hen selection practices, and causes of hatchability failure. Multistage sampling procedures were employed to select woredas, sample kebeles, and respondents, in which two districts were selected by purposive sampling technique; stratified purposive techniques were employed to select nine sample kebeles, and purposive random sampling techniques were used to select a total of 385 respondents. Pretested structured questionnaire and focused group discussion were employed to generate data. All generated survey data were analyzed using descriptive statistics of SPSS 16. Broody hens were the sole means of egg incubation and chick brooding. Broody hens are selected based on plumage color, egg yield, body weight (size), and mothering ability. Eggs laid at home were the predominant sources of incubation and were selected mainly based on egg type, egg age, and egg size. Clay pots, plastic, bamboo cages, and cartons were used as egg-setting materials, and grasses, straws, cotton seeds, feathers of broody hens, and clothes were used as bedding materials. October–December was the most preferred while July–September was the worst months of the year to incubate eggs and to achieve the best hatchability eggs. Environmental temperature, lack of proper laying nests, and post handling were the critical causes of the failure of egg hatchability in the study area. The total number of eggs incubated using a novel nest was 16 eggs. A comparatively high number of chicks were hatched during the second phase (7–12) from the number of eggs set. There is a strong need for training of chicken producers in increasing hatchability performances through the preparation of proper brooding nest or laying nest, egg selection, feeding, housing, health care, proper post handling, and chick management to increase their economic returns. Community-based holistic improvement programs are also very imperative to design to improve the genetic potential through selective breeding and conservation of the indigenous chicken genetic resources. Further research on hatchability performance evaluation of the indigenous chickens both on-farm and station as well as the effect of the 12 months of the year on incubation and hatchability of eggs.

The Effect of Ursolic Acid Addition into High-Energy Laying Hen Diet on Performance, Egg Quality Parameters, Serum Lipid Profile and Liver Fat Rate

This study was conducted to determine the effect of ursolic acid (UA) at different ratios (0, 0.5, 1 and 1.5%) supplementation into high-energy laying hen diet on performance, egg quality parameters, serum lipid profile, some liver enzymes and liver fat ratio. 
 A total of 120 Lohman LSL laying hens, 70 weeks old, were used in present study. The animals were divided into 5 groups and each group consisted of six subgroups. In the experiment, the control group was fed with basal feed, and the treatment groups were fed with high-energy (HE) diets including 0, 0.5, 1 and 1.5% UA, respectively. Experiment lasted for 8 weeks. Egg yield decreased in high energy feed groups except HE + 1.5% UA group. Egg weight was found to be highest in the HE + 1.5% UA group. Addition of UA into feed improved the feed conversion ratio (FCR). It was determined that liver fat ratio was higher in the group fed with HE feed (P

Reproductive indicators of sterlet and Siberian sturgeon when grown in aquaculture and in natural reservoirs

The biological indicators and results of spawning of sterlet and Siberian sturgeon on the example of fish farms with different industrial technologies of fish cultivation and different amounts of heat during the year are analyzed. The comparison of reproductive indicators of these species of different populations from natural reservoirs is carried out. It is shown that in the conditions of warm-water farms, producers of sterlet and Siberian sturgeon matured at a higher mass, mature oocytes reached larger sizes, but such indicators as the yield of eggs from the mass of the female and relative fertility decreased. The working fertility of sterlet depended on body weight, and, accordingly, was higher in fish grown in the conditions of the plant (43,000 thousand pieces). Sterlet of Siberian populations (Irtysh and Ob) matured at a lower weight than the Volga, and was distinguished by a large yield of caviar from body weight — up to 17%. In the Ob sturgeon in industrial conditions, with a larger mass of females, the working fecundity was less than in natural reservoirs. Wild sturgeon from the Lena River, maturing at a lower mass among all populations of Siberian sturgeon, was characterized by high relative fertility (12,8 thousand pieces/kg) compared with the domesticated form (5,4–6,0 thousand pieces/kg). When growing these species in aquaculture, the ratio of growth and fertility indicators changes markedly. In natural reservoirs, the maturation of germ cells and reproduction of sturgeon fish is largely determined by both the amount of heat and seasonal temperature changes, which ensures the synchronous development of gametes and the best reproductive performance.

Laying hen performance, feed economy, egg quality and yolk fatty acid profiles from laying hens fed live black soldier fly larvae

<br />The black soldier fly (<i>Hermetia illucens</i>) serves as an alternative source of protein in poultry production. However, there is little available information on feeding live black soldier fly larvae (LBSFL) to hens. The present study filled this gap by testing the effect of dietary LBSFL on laying hen performance, feed economy, egg quality, and yolk fatty acid composition. In total, one hundred forty-four 25-week-old Charoen Pokphand Brown laying hens were assigned to four groups. Experimental birds were provided a basal diet supplemented with 0.0 (T1), 10.0 (T2), 20.0 (T3), or 30.0 (T4) g/kg LBSFL. Our results indicated that no effects on body weight gain, egg yield, egg weight, or egg mass (<i>P</i> > 0.05) were observed in any of the dietary LBSFL groups. The addition of 10.0 g/kg LBSFL decreased feed intake, feed conversion ratio, and feed cost (<i>P </i>< 0.05), contrary to two higher doses of LBSFL. Similarly, the egg quality parameters were not influenced (<i>P ></i> 0.05) by the dietary LBSFL except for the egg yolk colour which significantly decreased with increasing LBSFL levels. Furthermore, the values for lightness (L*), redness (a*), and yellowness (b*) of the egg yolk were different (<i>P <</i> 0.05) between the four treatments. Paler egg yolk was found in the 20.0 and 30.0 g/kg LBSFL groups compared to the control group (<i>P <</i> 0.05). Significantly lower deposition of C18:3n6 was found for 30.0 g/kg, whereas there was a significant decrease in deposition of C22:6n3 with all LBSFL groups (<i>P</i> < 0.05). C20:3n6 levels, on the other hand, increased significantly in the 20.0 g/kg LBSFL group (<i>P</i> < 0.05). Thus, feeding LBSFL has no potential to increase the proportion of anti-inflammatory n-3 fatty acids. From an economic point of view, it is advantageous to feed the hens a dose of 10 g/kg LBSFL.

Evaluation of reproductive and productive qualities of roosters of different lines of the IZA-F-15 cross

Artificial insemination of poultry allows for an increase in reproductive qualities, reduces feed costs for products, and improves breeding work. The authors evaluated the reproductive and productive attributes of roosters of two different lines on adult birds of the IZA-F-15 cross by phases and during the effective period. All hens in both groups belonged to the maternal form of this cross. It was found that the males of the M-22 line were superior to their peers of the M-99 line in terms of ejaculate volume and the number of sperm per 1 ml in the productive period phases and for the entire cycle of their use. The sperm parameters (number of standard forms of spermatozoa and their motility) were similar in both groups of roosters and amounted to 71.35 - 73.79% and 7.07 - 7.5 points, respectively. Roosters of the M-22 line were superior to those of the M-99 line in terms of a set of indicators of reproductive qualities (ejaculate volume, sperm count per 1 ml, fertility and hatching egg yield). Differences in hands were statistically significant. However, the egg production of laying hens and the average weight of their eggs were high. Using males of different lines in artificial insemination did not reveal significant differences in these indicators. The fertility of eggs and the yield of hatching eggs significantly increased in hens inseminated with the sperm of M-22 roosters (group 2), compared with the control, respectively, from 95.94 to 97.33 and from 89.14 to 91.14%. At the same time, the output of broiler chickens in both groups was at a high level and almost the same (80.21 and 82.25%).

Poultry Management Strategies to Alleviate Heat Stress in Hot Climates: A Review

Heat stress remains a major challenge affecting poultry production in sub-tropical and tropical environments; hence it continues to receive attention. The present study aimed to discuss heat stress and its effects on poultry production and suggests mitigation strategies to combat the effects of increased environmental temperature on poultry performance. Poultry raised in hot climates suffers from heat stress, which reduces meat and egg production, reproductive performance, feed intake, and feed conversion efficiency leading to poor growth rates. Reduced feed intake results in a reduction in meat quality, growth, egg yield, and quality. A decrease in feed utilization efficiency is the major cause of poor growth performance in hot environments. To counteract the negative impacts of high ambient temperatures on the performance of poultry, a wide range of management practices are widely used, including nutrient manipulations (particularly protein and energy), electrolyte and vitamin supplementation, feed form (especially particle size and moisture content), choice feeding, controlled feeding, time of feeding, wet feeding, water management, and use of new breeds that thrive well in hot environments. These management practices help lower heat load and facilitate evaporative cooling, all of which may positively impact poultry performance and health. Keywords: Choice feeding, Feed conversion efficiency, Heat stress, Poultry production

Effects of Dietary Rare Earth Chitosan Chelate on Performance, Egg Quality, Immune and Antioxidant Capacity, and Intestinal Digestive Enzyme Activity of Laying Hens.

Rare earth chitosan chelate salt (RECC) is a potential feed additive and is a product of the chelation effect between rare earth ions and chitosan. This research study aims to explore the effects of dietary RECC on performance, egg quality, intestinal digestive function, and the immune and antioxidant capacity of laying hens in the late phase of production. A total of 360 56-week-old Dawu Jinfeng laying hens were randomly allotted into four treatment groups with six replicates per treatment and 15 birds per replicate. The laying hens were fed the basal diet supplemented with, respectively, 0 (control: CON), 100 (R1), 200 (R2), and 400 (R3) mg/kg for 8 weeks. Dietary RECC significantly improved average daily feed intake (ADFI) and average daily egg yield in both linear and quadratic manner (p < 0.05). In addition, albumen height and HU were improved significantly (p < 0.05) in a dose-dependent manner of RECC. In addition, a significant decrease (p < 0.05) in serum TP, IgA, and MDA for the R1 group and IgG in the R2 group were notable, while the increase in serum TP and decrease in T-AOC were found for R3 dietary group compared to CON (p < 0.05). The level of intestinal IL-2 and TNF-α was decreased by dietary RECC (p < 0.01). The activities of the digestive enzyme (α-Amylase, lipase, and Trypsin) showed a quadratic change with an increase and then decrease in response to increasing dose of RECC, 200 mg/kg RECC significantly increased the activity of lipase and Trypsin (p < 0.01). Supplementation of dietary RECC at low doses compared to higher doses impacted positive effects on the antioxidant capacity and immune function (p < 0.05). The utilization of RECC as a feed additive in the diet of aged laying hens exerted beneficial effects on egg production, albumen quality, humoral immunity, inflammatory response, and activity of digestive enzymes. Thus, the regulation of antioxidant capacity and duodenal function via increased enzyme activity and immune and inflammatory response were critical to the improvement of laying performance and egg quality in aged hens. The optimal supplemental dose is 100-200 mg/kg.

Genetic and phenotypic parameter estimates for selection within Ugandan indigenous chickens

The high genetic variation within indigenous chickens (IC) which provides an opportunity to select superior stock for sustainable production and conservation is under-exploited. This study is aimed at estimating heritability and genetic and phenotypic correlation coefficients of productive and reproductive traits of Ugandan IC as a basis for selection. Data on traits were collected across two consecutive generations, weight (W) and shank length (SL) of chicks at hatching (HW) as well as at 2 (W2; SL2), 4 (W4; SL4), 6 (W6; SL6), 8 (W8; SL8), and 12 (W12; SL12) weeks of growth. Body weights at onset of lay (WFE) were also measured. In addition, egg number (EN-60), egg weight (EW), clutch number (CLN-60), and clutch size (CLS-60) over a period of 60 days were recorded. Genetic parameters were estimated using the univariate animal model analysis with restricted maximum likelihood procedure using the variability package of R, version 4.1.1. Heritability of traits ranged from 0.30 and 0.72 except SL4 (0.02), SL12 (0.14), and EN-60 (0.17). The traits EN-60 and W4 were negatively phenotypically correlated (- 0.49). Body weight at first egg was highly genetically correlated (0.99) with SL8. Egg number was significantly, negatively, and genetically correlated (- 0.96) with SL12. In conclusion, shank length is a potential phenotypic marker when selecting for live weight at onset of lay and egg yield. The shank length could, therefore, permit selection of superior chickens at an early age.

Protection of SPF Chickens by H9N2 Y439 and G1 Lineage Vaccine against Homologous and Heterologous Viruses.

Prior to the identification of low pathogenic avian influenza H9N2 viruses belonging to the Y280 lineage in 2020, Y439 lineage viruses had been circulating in the Republic of Korea since 1996. Here, we developed a whole inactivated vaccine (vac564) by multiple passage of Y439 lineage viruses and then evaluated immunogenicity and protective efficacy in specific-pathogen-free chickens. We found that LBM564 could be produced at high yield in eggs (108.4EID50/0.1 mL; 1024 hemagglutinin units) and was immunogenic (8.0 ± 1.2 log2) in chickens. The vaccine showed 100% inhibition of virus in the cecal tonsil with no viral shedding detected in either oropharyngeal or cloacal swabs after challenge with homologous virus. However, it did not induce effective protection against challenge with heterologous virus. An imported commercial G1 lineage vaccine inhibited viral replication against Y280 and Y439 lineage viruses in major tissues, although viral shedding in oropharyngeal and cloacal swabs was observed up until 5 dpi after exposure to both challenge viruses. These results suggest that a single vaccination with vac564 could elicit immune responses, showing it to be capable of protecting chickens against the Y439 lineage virus. Thus, our results suggest the need to prepare suitable vaccines for use against newly emerging and re-emerging H9N2 viruses.

Comparative transcriptomic analysis reveals candidate genes for seasonal breeding in the male Lion-Head goose

ABSTRACT 1. Due to seasonal breeding, geese breeds from Southern China have low egg yield. The genetic makeup underlying performance of local breeds is largely unknown, and few studies have investigated this problem. This study integrated 21 newly generated and 50 publicly existing RNA-seq libraries, representing the hypothalamus, pituitary and testis, to identify candidate genes and importantly related pathways associated with seasonal breeding in male Lion-Head geese. 2. In total, 19, 119 and 302 differentially expressed genes (DEGs) were detected in the hypothalamus, pituitary and testis, respectively, of male Lion-Head geese between non-breeding and breeding periods. These genes were significantly involved in the neuropeptide signalling pathway, gland development, neuroactive ligand-receptor interaction, JAK-STAT signalling pathway, cAMP signalling pathway, PI3K-Akt signalling pathway and Foxo signalling pathway. 3. By integrating another 50 RNA-seq samples 4, 18 and 40 promising DEGs were confirmed in hypothalamus, pituitary and testis, respectively. 4. HOX genes were identified as having important roles in the development of testis between non-breeding and breeding periods of male Lion-Head geese.