Chick Weight Research Articles

Effect of Day-Age Chick Weight, Finger Length, Shank Length and Chick Length on Carcass Characteristics and Internal Organ Weights of Broiler Chickens

This study was carried out to investigate the effects of some body measurements (chick weight, finger length, shank length, chick length) of day-old broiler chicks on carcass characteristics and edible yields. In the study, 192 day-old male broiler chicks were used. Broiler chicks were first divided into 4 groups according to treatment groups (chick weight, finger length, shank length, chick length), and then each group was divided into two groups according to weight (heavy-light) or length (long-short). From body criteria; chick weight ≥47.7 and

Matrix metalloproteinase 7 (MMP7) as a molecular target for Mycoplasma gallisepticum (MG) resistance in chickens.

Mycoplasma gallisepticum (MG) causes chronic respiratory disease (CRD), posing a significant threat to global poultry production. Current preventive strategies face limitations, emphasizing the need for alternative approaches such as breeding for disease resistance. This study identifies the matrix metalloproteinase 7 (MMP7) gene as a key factor in CRD resistance. Analysis of high-throughput sequencing data revealed MMP7's association with MG infection at tissue and cellular levels. Overexpression of MMP7 in avian type II alveolar epithelial cells (AECII) and macrophages (HD11) inhibited MG adhesion, modulated immune responses, and suppressed MG-induced cell proliferation and apoptosis, though MG replication remained unaffected. Conversely, MMP7 inhibition enhanced MG infection. Experimental infections in commercial (Jingfen Layer No.6, Hy-Line White) and local Chinese chicken breeds (Guangxi Indigenous, Tianlu Partridge, Cyan Shank Partridge) validated Tianlu Partridge chickens' relative resistance and Jingfen Layers' susceptibility. MMP7 expression levels correlated positively with reduced chick weight, air sac damage, tracheal mucosal thickness, and MG lung loads. These findings highlight MMP7 as a molecular target for assessing MG susceptibility and breeding resistant chickens while demonstrating the utility of local Chinese breeds in resistance-focused breeding programs.

Effects of lifetime feeding of hydrolyzed yeast to broiler breeders on egg production, quality, and hatchling attributes.

The effects of lifetime feeding of hydrolyzed yeast (HY) to broiler breeders (BB) on egg production, egg quality, and hatchling attributes were investigated. The birds were selected from two groups reared on diets with or without 0.05 % HY from hatch. The birds were placed for the current study at 22 weeks of age (woa) in 16-floor pens (20 ♀ and 2 ♂/pen) based on rearing diet identity. Isocaloric and isonitrogenous diets were formulated without or with 0.05 % HY for three production phases: 1 (22 to 40 woa), 2 (41 to 50 woa), and 3 (51 to 64 woa) and allocated within rearing diet identity in a completely randomized block design (n = 8). The birds had free access to water, whereas feed allocation was per breeder guidelines. Egg count/ pen was recorded four times daily from 25 woa (the time point the first egg was laid) to calculate hen day egg production (HDEP), and cumulative eggs per hen housed (CEPHH). From 28 woa, eggs were selected randomly for eggshell breaking strength (ESBS) and eggshell thickness (EST) and for incubation to determine fertility, hatchability, in-ovo mortality, chick sex ratio, and chick weight. Two hens per pen were necropsied at 44 and 64 woa for breast, abdominal fat and liver weights. There were no (P>0.05) interactions between diet and BB age or the diet effects on response criteria. Broiler breeder age effect (P<0.05) was such that HDEP, ESBS, EST, hatchability declined whereas egg weight, in-ovo mortality, and chick to egg weight ratio increased with age. Control birds had more (P=0.015) CEPHH (25 to 64 woa) than HY40 birds. In conclusion, the more CEPHH for the control group was reflective of hen mortality whereases the broiler breeder age effects were as expected. Overall, lifetime feeding HY to broiler breeders from hatch had no impact on egg production rate, egg quality and hatchling attributes.

Influence of Eimeria spp. and Clostridium perfringens Infection on Growth Performance and Toltrazuril Residues in Chickens.

Coccidiosis and necrotic enteritis are among the most common diseases affecting poultry, with economic impact due to reduced production and the costs of treatment and prevention. Eimeria invasion contributes to gut damage that promotes the growth of other harmful pathogens, such as Clostridium perfringens. Coccidiostats, with toltrazuril as an example, are widely used to control these infections. In this study, we assessed the effects of Eimeria spp. infection and coinfection with Eimeria spp. and Clostridium perfringens on chicken weight and toltrazuril concentrations, along with two metabolites-toltrazuril sulfoxide and toltrazuril sulfone-using liquid chromatography coupled with mass spectrometry. The analysis of liver and muscle samples showed lower levels of residues in groups challenged with Eimeria spp. In the case of combined Eimeria and C. perfringens infection, no significant differences were observed. These findings suggest that the combination of Eimeria and C. perfringens does not significantly alter the residue levels of toltrazuril and its metabolites, providing valuable insight into the pharmacokinetics of toltrazuril in poultry under infection conditions. This research contributes to optimizing drug use and residue management in poultry production.

Broadband Long Wavelength Light Promotes Myopic Eye Growth and Alters Retinal Responses to Light Offset in Chick.

Prolonged exposure to broadband light with a short-wavelength (blue) or long-wavelength (orange/red) bias is known to impact eye growth and refraction, but the mechanisms underlying this response are unknown. Thus, the present study investigated the effects of broadband blue and orange lights with well-differentiated spectrums on refractive development and global flash electroretinography (gfERG) measures of retinal function in the chick myopia model. Chicks were raised for 4 days with monocular negative lenses, or no lens, under blue, orange, or white light. Chick weight, eye dimensions, and refraction were measured at the conclusion of rearing. In a separate cohort of chicks, the effect of 4 days of colored light rearing on retinal responses to orange, blue, or white light flashes was assessed using gfERG. Chicks reared under orange light for 4 days exhibited a significantly larger myopic shift in response to negative lenses compared to those reared under blue light. Orange light rearing for 4 days increased the gfERG d-wave amplitude and implicit time in response to orange light flashes but did not alter responses to white or blue flashes. Blue and white light rearing did not affect the retina's response to light flashes of any color. Orange light rearing exacerbated defocus-induced myopia relative to blue light rearing. The gfERG recordings revealed that prolonged orange light exposure increased retinal responsivity to the offset of long wavelength light flashes, suggesting a potential role for ON/OFF pathway balance in generating the refractive response that requires further electrophysiological and molecular investigation.

Phenotypic Variabilities in Strain and Sex of Two-Broiler Chickens at Different Ages

Owing to the growing number of animal breed development centres around the world and the profitability of their production, comparative studies to evaluate superior strain and sex performance in breeders became an important endeavour for researchers. Hence, this study was designed to evaluate the effects of strain and sex on body weight and linear body morphometric traits of 2-broiler chickens during the starter and finisher phases. Arbor-Acre and Cobb-500 chicks (n=192) were raised under controlled conditions and monitored over 56 days. Weekly measurements of body weight and linear body traits were recorded. Data subjected to multivariate analysis using the SPSS package revealed that strain significantly (p&lt;0.05) influenced growth, with Arbor-Acre broilers exhibiting superior body weight performance, particularly during the starter phase, weighing 799.50g compared to 669.11g for Cobb-500. This result implied that selecting for improved growth performance during the starter phase (week four) was an important consideration for breeding farms. However, the sex and age factors, as well as the linear body traits in both strains, yielded similar economic results at 8 weeks. Male broilers consistently outperformed their female counterparts in body morphometric traits during both phases. The sex-based differences observed in this study varied across developmental stages, emphasizing the importance of sexual dimorphism in broiler management. These findings recommended that strain and sex were important factors to consider in optimizing broiler production, providing critical insights for broiler breeders and farmers to enhance production efficiency through strategic selection of strains, sex, and other environmental factors.

Metabolism and productivity of broiler chickens when use a complex of organic acids

In industrial conditions, unsatisfactory organoleptic indicators of drinking water such as hardness, microbial contamination, algae and mold in the drinking system, as well as high pH, to increase the pressure on poultry by pathogenic microfl ora. One of the ways to normalize microfl ora in vivo is to include organic acids in the diet. Acidifi ers, improving the taste of drinking water, have proven themselves well in its purifi cation. The purpose of the research was to study the metabolism and productivity of broiler chickens when using the organic acid complex BiSAlTek. The use of the acidifi er BiSAlTek in doses of 1.5; 2.0 and 2.5 l/t was studied. It was established that the absolute increase in live weight of chickens for the entire rearing period by groups was: in the 1st control group 2154.7±64.3 g, and in the 2nd, 3rd and 4th experimental groups (the dose of the drug: 1.5, 2.0 and 2.5 l/t of water, respectively) – 2261.2±47.7 (p &gt; 0.05), 2263.0±9.0 (p &gt; 0.05), 2335.5±8.2 g (p &lt; 0.01), respectively, which was 4.9, 5.0 and 8.4 % more than in the 1st control group. The average daily live weight gain over the entire experimental period in the 2nd, 3rd and 4th experimental groups was 56.7±1.7 (p &gt; 0.05), 59.5±1.3 (p &gt; 0.05) and 61.4±0.2 g (p &lt; 0.01), which exceeded the similar indicator in the broilers of the control group (56.7±1.7 g) by 4.9, 5.1 and 8.3 %, respectively. Thus, a positive eff ect of the acidifi er BiSAlTek was noted regardless of the dose of the drug. The greatest reliable diff erence was noted in the 4th experimental group at the dose of drug BiSAlTek equal to 2.5 l/t of water. The use of the acidifi er BiSAlTek at doses of 1.5, 2.0 and 2.5 l/t contributed to an increase in profi t by 12.8, 14.6 and 21.7 % as a result of an increase in the viability of chickens by 2.0, 4.0 and 4.0 abs.% and lower feed costs per 1 kg of live weight gain by 9.0, 12.0 and 15.0 %, respectively, relative to the control.

Effects of Local Chicken Strain and Phytobiotics Supplementation on Body Weight and the Percentage of Lymphoid Organ Weight

Phytobiotics consist of various herbs and their derivatives which are widely used as growth promoters, antimicrobial, anti-oxidative, and other properties. The purpose of this study was to ascertain how the strain of local chickens and phytobiotics interacted with body weight and the percentage of weight in lymphoid organs. A total of 480 birds, comprising Kampung chicken, Kampung unggul Balitbangtan (KUB) chicken, and Kedu chickens, made up the research material. The phytobiotics and basal diet included 1% sambiloto, 1% garlic, and 1% kalimun. A completely randomized design factorial pattern was employed in the experiment. The analysis of variance was used to examine the data. The analysis of variance revealed that there was no significant (p&gt;0.05) impact on the body weight and percentage of lymphoid organ weight of local chickens from the interaction between phytobiotics feeds and local chicken lines. The proportion of thymus and bursa of fabricius weights, as well as body weight, were significantly (p&lt;0.05) impacted by the chicken strain. The local chicken's body weight was significantly affected (p&lt;0.01) by a 1% phytobiotic supplement. Local chickens' body weight and percentage of lymphoid organ weight were not significantly impacted (p&gt;0.05) by the interaction between local chicken strain and phytobiotics diets, according to the analysis of variance results. KUB chickens have a higher lymphoid organ than Kampung and Kedu chickens. Supplementation with 1% sambiloto reduced the body weight of local chickens.

Effects of Formula Product Injection on Hatching Parameters, Small Intestinal Development and Ileum Histology in Breeder Chicken Eggs.

This study aimed to determine the effects of in ovo formula product injection on hatching parameters, chick quality, small intestinal development and ileum histology of breeder hen eggs. A total of 400 fertilised eggs were obtained from the Atak-S parent flock at 42 weeks of age for the experiment. The experiment was designed in two groups: a control group (C), in which no injection was performed, and the other group in which a solution containing formula products at concentrations of 1.25% (F1), 2.5% (F2) and 5% (F3) was injected into 0.5mL/egg air sac. The hatching rate, embryonic mortality and discard chick rate were examined at the end of the trial. The best result of the hatching rate was found in the Group F2, while there was no difference between the control and Group F1 regarding these parameters. The weight and length of the quality chicks were promoted in the Group F1. In Group F3, the injection of the formula product at a rate of 5% had a negative effect on parameters such as hatchability, embryonic mortality, chick length, Pasgar score and yolk sac weight compared to the other groups. Otherwise, in Group F2, there was a significant increase in villus height, crypt depth and lamina muscularis mucosa thickness compared to the other groups (p<0.01). As a result, it has been concluded that the appropriate rates for the formula product application on chicks are 1.25% and 2.5%, considering the positive effects of the 1.25% and 2.5% rates and the negative effects of the 5% rate.

The effect of the "Hydro Rex Vital" drug on zootechnical and economic indicators of broiler chickens.

The effectiveness of the anti-stress drug "Hydro Rex Vital" in the rearing of broiler chickens during the transitional period of the year was studied. The study was conducted on broiler chickens of the "Arbor Acres" crossbreed at the farm of "Altynbek" LLP (Almaty region, Isayev village). Four groups (one control and three experimental) were formed using the analogy method at the age of one day. The chickens of all groups were kept in the same room (identical sections) on deep litter until the age of 42 days. The drug was not used in the control group 1, while in the experimental groups 2, 3, and 4, the dosage of the drug administered with drinking water was 200, 300, and 400 ml per 1 ton of water, respectively. The results of the study showed that the survival rate in groups 1 (control), 2, 3, and 4 was 90.0%; 93.3%; 96.7%; 96.7% respectively; live weight of chickens at the age of 42 days was 2.49; 2.60; 2.65; and 2.57 kg respectively; average daily weight gain was 58.3; 60.8; 62.0; and 60.0 g respectively; feed consumption per 1 kg of live weight gain was 1.85; 1.74; 1.69; and 1.57 kg respectively; the slaughter yield of eviscerated carcasses was 72.2; 74.9; 76.3; and 74.0% respectively; production profitability was 170; 263; 313; and 308% respectively. It is recommended to give the anti-stress drug "Hydro Rex Vital" to broiler chickens with water at a dosage of 300 ml per 1 ton of water from the age of one day until the end of the rearing period to improve viability and productivity, reduce feed costs per unit of product, and meat production cost, and increase production profitability. In research, it is advisable to use the Russian production efficiency index instead of the European productivity index to quickly determine the winning group.

Efficacy of anticoccidial drugs and their impacts on growth performance on caecal coccidiosis in broiler chicken

Coccidiosis is a fatal disease of poultry. In order to combat caecal coccidiosis of broiler, this study was designed to evaluate the comparative efficacy of sulfaclozine, toltrazuril and amprolium. 50 pcs of day old broiler chick were randomized and divided into five groups. The chicks of group T0 kept as non-infected, non-medicated control. The group Ti were kept as infected non treated and other three groups such as T1, T2, T3 were treated with sulfaclozine, toltrazuril and amprolium at a dose rate of 10 mg/kg body weight orally, respectively on day 21 and 24 of age. In chicks of group T1, sulfaclozine was given at rate of 10mg/kg body weight orally. Similarly chicks of group T2 were treated with toltrazuril 10 mg/kg and group T3 were treated with amprolium at the rate of 10 mg/kg body weight orally, respectively. After treatment, the efficacy, body weight, morbidity and mortality were studied. From the present research treatment there were sharp decline of OPG counts in all groups. But the decline was very significant (P&lt;0.05) in Group T3 which was 1.37±0.002 thousand. This study also suggested that the mean initial weight of chicks for all groups were almost similar, which was 37 g and above as recorded on day 1. The pre-infection body weight values at day 10 recorded for all groups were almost similar which was more than 217 g. Significant (P&lt;0.01) increase of body weight was recorded on day 21 following which the highest increase (780.21±1.29 g) was seen in Group T0 chicken (healthy control). After treatment (on day 24), there were significant increase in body weight of all groups used for therapeutic trial with the maximum mean weight gain in Group T3 (790.83±2.10g) which was the nearest value to Group T0 (healthy control). The clinical signs of caecal coccidiosis appeared on day 15 and became severe on day 21. A total of 6 chicks died during the experimental period from Group Ti (untreated affected group) and found 60% mortality. Only 3 birds died in Group T1 treated with sulfaclozine and 2 birds died in group T2 treated with toltrazuril and 2 birds died in group T3 group treated with amprolium.

Features of the microstructure of the quadriceps femoral muscle of broiler chickens of the smena-9 cross with various feeding diets

The article presents the results of studies of the histological and ultrastructural characteristics of the quadriceps femoral muscle of broiler chickens of the Smena-9 cross on the 35th day of postembryonic ontogenesis using feed additives (probiotic, prebiotic, sorbent) of domestic production in addition to the basic feeding diet.The work was implemented within the framework of the thematic task plan for the implementation of research works under the state order of the Ministry of Agriculture of the Russian Federation (Agreement No. 082-03-2023-238 dated 30.01.2023) on the topic: "Development of theoretical foundations and methodology for the practical use of morphological criteria in assessing the quality and safety of poultry products." It has been shown that against the background of the use of feed additives, an increase in the weight of chickens occurs. At the same time, the microstructure of the rectus head of the quadriceps femoris of birds of the control and experimental groups, while maintaining the general plan of structure (the presence of muscular and connective tissue components, bundle organization), is not the same. Based on studies using light and transmission electron microscopy, it was shown that the signs of morphological maturity of skeletal muscle tissue are most pronounced when using a probiotic, in the case of using a prebiotic and a sorbent, muscle fibers grow less synchronously, which is manifested by the variability of their thickness. The thickness of muscle fibers, their bundles, the state of the mitochondrial apparatus, the packing density of myofibrils and their thickness, the degree of development of endomysium and perimysium and the presence of white adipose tissue can be objective morphological and morphometric criteria for assessing the condition of muscle tissue, which correlates with the taste qualities of poultry meat. Data on the structural organization of the quadriceps muscle of the new domestic cross expand the theoretical base in the field of the myology of farm birds, including in terms of identifying morphological signs of the realization of genetic potential against the background of the use of different feeding diets in chicken rearing technology, which allows us to quickly assess the effectiveness of chicken rearing technology and predict an increase in productivity.

The effect of the in ovo injections of dextrin and L-carnitine in conditions of thermal stress during the incubation period on the embryonic development and growth of broiler chickens

The embryonic thermal stress due to the overheating is a common problem of the incubation of broiler eggs and hence the search for the methods of metabolic corrections of the related shifts in the embryonic development can be practically actual task. The aim of the research was to study the effect of the in ovo injections of heat stressed chicken embryos with the combination of dextrin (as glucose source) and L-carnitine on the efficiency of incubation and early postnatal growth rate. The study was performed in 2020 on incubated eggs, embryos and chicken of Cobb-500 final hybrid cross. Three groups of eggs (n = 62) were formed for each temperature regime of incubation: without injections, physiological saline injection, injections with the solutions of dextrin (10%) and L-carnitine (0.6%). The eggs were injected with physiological saline, the solutions of dextrin and L-carnitine at the 17th day of incubation. Then the incubation was carried out in hatchers at normal temperature (37.2 °С) and increased temperature (38.5–39.0 °С). The increased temperature during hatching period on average among the groups decreased the hatchability of eggs by 6.1 % and relative weight of chicken by 0.96 %. The injection in ovo with the mixture of dextrin and L-carnitine 1.6–3.2 % increased the hatchability of eggs incubated at increased and normal temperature, respectively. The live weight of day-old chicks injected in ovo with the solution of dextrin and L-carnitine at normal temperature was significantly higher by 1.3–2.3 % (p &lt;0.05) as compared with control groups. Neonatal growth rate was higher in chicken injected in embryonic period with dextrin and L-carnitine both at normal and increased temperature – live weight of 7-day chicken of the experimental groups was 5.9 and 5.1 % higher (p &lt;0.05) compared with the control groups of the same temperature regime. In chicken incubated at increased temperature the differences remained to 35 days of age and were 5.7 % (р &lt;0.05). Biochemical variations were noted in blood parameters of embryos of the control and experimental groups that proved the absorption of exogene nutrients and biologically active substances by the embryo. Thus, in blood plasma of 17-day embryos injected in ovo with the solution of dextrin and L-carnitine the concentrations of glucose significantly increased by 1.6-1.7 % (p&lt; 0.001) and triglycerides by 46.2 % (p &lt;0.05). So, by injecting the incubated eggs during hatching period with the solution of dextrin and L-carnitine, the neonatal growth rate of chicken raised at normal and increased temperature and during heat stress as well. No significant effect of the injection on the hatchability of eggs in conditions of thermal stress in the hatching period was found.

Effect of Thermal Manipulation During Embryogenesis on Pre and Post-Hatch Performance of Stored Hatching Eggs of Japanese Quails

This research investigated the influence of high incubation temperature on hatching, and post-hatch characteristics of stored hatching eggs of Japanese quails. Hatching eggs of Japanese quails were stored for 7 days and incubated under two temperature conditions. The T1 group (control, 75 eggs) was subjected to a standard incubation temperature (37.5°C) while the T2 group (75 eggs) was exposed to a thermal manipulation protocol (of 38.5°C for 5 hours daily between embryonic days 5-15. The egg weight classification, chick weight, chick length, wing length, weekly body traits, body weight, total feed intake, and stress responses, weight of internal organs, whole carcass, breast, neck, wing, thigh, and neck did not significantly differ (P&lt;0.05) between the incubation treatments. Hatchability was higher and early embryonic mortality was lower in T2 than in T1. Late embryonic mortality was lower in T1. Significantly (P≤ 0.05) higher pectoral muscle width at hatch and carcass yield/dressing percentage were observed in quails exposed to thermal manipulation protocol during embryogenesis. It was concluded that exposure of stored eggs to thermal manipulation protocol (of 38.5°C for 5 hours between embryonic days, ED 5-15, T2) during embryogenesis could enhance embryonic and growth traits, as well as carcass traits without any negative effect on stress indicators.

The relationship between mitochondrial DNA haplotype and its copy number on body weight and morphological traits of Wuliangshan black-bone chickens.

Mitochondria play a pivotal role as carriers of genetic information through their circular DNA molecules. The rapid evolution of the D-loop region in mitochondria makes it an ideal molecular marker for exploring genetic differentiation among individuals within species and populations with close kinship. However, the influence of mtDNA D-loop region haplotypes and mtDNA copy numbers on phenotypic traits, particularly production traits in chickens, remains poorly understood. In this comprehensive study, we conducted D-loop region amplification and sequencing in the blood mitochondria of 232 female Wuliangshan black-bone chickens. Our investigation identified a total of 38 haplotypes, with a focus on 10 haplotypes that included more than five individuals. We meticulously analyzed the correlations between these haplotypes and a range of traits, encompassing body weight, tibial length, tibial circumference, body oblique length, chest width, and chest depth. The results unveiled significant disparities in specific tested traits across different haplotypes, indicating a tangible association between mtDNA haplotypes and traits in chickens. These findings underscore the potential impact of mitochondrial DNA variations on energy metabolism, ultimately leading to divergent chicken phenotypes. Furthermore, our examination revealed positive correlations between mtDNA copy numbers and tested traits for select haplotypes, while other haplotypes exhibited non-uniform relationships between traits and mtDNA copy numbers. In addition, phylogenetic analysis disclosed the involvement of two subspecies of red jungle chicken in the origin of Wuliangshan black-bone chickens. Consequently, our research contributes novel insights into mitochondrial genomic selection, augments comprehension of the roles played by haplotypes and mtDNA copy numbers in chicken population genetics and phylogenetic analysis, and furnishes fundamental data crucial for the preservation and provenance determination of black-bone chickens.

Evaluation of the Effect of Probiotics on Growth Performance in Backyard Poultry Farming

Early chick mortality is a common issue in improved germplasm of desi birds under backyard system of rearing. Probiotics is one of the feed additives to decrease chick mortality. Hence, the present study aimed to evaluate the effect of probeads EC on growth performance and livability of vanaraja chicks. This study was conducted at Mangalapuram and Thussur villages of Namakkal district. A total no of 400 nos of vanaraja chicks were distributed to 4 woman groups. Each group consists of 4 replicates with 20 chicks in each. Group I was taken as control (C), Group II was supplemented with probeads EC once in two days (T1), Group III was supplemented with probeadsEConce in a week (T2) and Group IV was supplemented with probeads EC only day old chicks (T3) and Group V was supplemented with oxytetracycline continuously three days from day old (T4). All the treatment groups were supplemented with 5 beads per bird. The present study revealed T1was significantly (P&lt;0.05) increased body weight compared to T2, T3 and control during second and fourth weeks of age of vanaraja chicks. The livability of vanaraja chicks was 87.21, 86.43, 83.52, 79.23 &amp; 77.26 % in T4, T1, T2, control and T3 respectively. The present study concluded that supplementation probeads EC once in two days increased body weight and livability of vanaraja chicken compared to control.

Impact of late-stage hypoxic stimulation and layer breeder age on embryonic development, hatching and chick quality.

The present study examined the effects of breeder age and oxygen (O₂) concentrations during the late chorioallantoic membrane (CAM) growth stage on embryo development, hatching dynamics, chick quality, bone mineralization and hatchability. A total of 1200 eggs from 33- and 50-week-old ISA layer breeders, weighing 53.85 g and 60.42 g on average respectively, were incubated at 37.7°C and 56 % relative humidity. From embryonic day (ED) 13 to 15, experimental eggs were exposed to hypoxia (15 % or 17 % O₂ for 1 hr/day) while the control was at 21 % O₂. Results showed significant interactions (p = 0.040) between breeder age and oxygen level, with embryos exposed to 15 % and 17 % O₂ exhibiting slower growth by ED 17. However, embryo weight at internal pipping (IP) was unaffected (p > 0.05). At hatch, chick weights were higher in hypoxic groups due to increased yolk sac retention (p = 0.024), while yolk-free weights were influenced only by breeder age (p < 0.001). Hypoxia at 15 % O₂ reduced chick length, toe length, and tibia parameters (p < 0.05), likely due to impaired calcium and phosphorus absorption. Embryos exposed to 15 % O2 had longer internal and external pipping events, delaying hatch time. Embryonic mortality was highest (p < 0.001) at 15 % O₂, contributing to the reduced hatch of fertile eggs. This research demonstrates that controlled hypoxic conditions can slow embryonic development, conserve yolk nutrients, improve organ maturation and chick weight across breeder ages.

Hatching Traits and Post-Hatch Performance of Broiler Chickens on In Ovo Feeding of Aqueous Extracts of Garlic, Mushroom and Their Combination

Abstract Feeding embryos with exogenous feed components prior to hatching has been reported to positively improved the growth and immune response in poultry. This study investigated the effects of in ovo administration of aqueous extracts of garlic, oyster mushroom and their combination on hatching traits and post-hatch performance of broiler chickens. A total of 230 broiler hatching eggs were sorted and incubated. On candling, 200 (85.11 % fertility) fertile eggs were obtained and distributed into five treatments: control, in ovo injection of garlic, oyster mushroom, combination of garlic and oyster mushroom, and de-ionized water (SHAM) at 0.1 ml.egg-1 in each treatment. In ovo injection was done on 18th day of incubation. Data collected were subjected to One-Way Analysis of Variance. Chick weight was the highest (P &lt; 0.05) in birds hatched from eggs injected with aqueous extracts of garlic (50.91 g per chick). The highest proportions (P &lt; 0.05) of heart (0.65 %) and spleen (0.18 %) were observed in birds from eggs injected with oyster mushroom and the combination of garlic and oyster mushroom, respectively. Significantly highest lymphocyte counts (P &lt; 0.05) were found in birds from eggs injected with aqueous extracts of garlic, and the combination of garlic and oyster mushroom. The best (P &lt; 0.05) feed conversion rate (FCR) (1.82) was recorded in birds from eggs on in ovo injection of aqueous extract of oyster mushroom. The study suggests that in ovo injection of aqueous extracts of garlic and oyster mushroom at 0.1 ml per egg can enhance chick weight, heart, spleen functions and overall growth performance in broiler chickens.

Experience and trust: the benefits of mate familiarity are realized through sex-specific specialization of parental roles in Cassin's auklet.

Maintaining a pair bond year after year (perennial monogamy) often enhances reproductive success, but what familiar pairs are doing differently to improve success is unknown. We tested the hypothesis that endocrine changes mediate improvements in parental attendance in known-age Cassin's auklets Ptychoramphus aleuticus, for which we found limited evidence. Instead, we found sex-specific parental roles in familiar pairs. Males modulated their nest attendance depending on the attendance of their mate, but the direction depended on mate familiarity. We suggest his flexibility may be mediated by prolactin. In a historical dataset, females with a familiar mate laid larger eggs that hatched into more robust chicks, but larger eggs correlated with lower female body condition. In study birds, attendance by males and females in good condition predicted chick weight, but attendance by females in poor condition did not, suggesting female-specific energetic constraint. Our findings suggest that males and females contribute differently to their joint reproductive fortunes, and that improvements in their respective roles may result in the benefits of mate familiarity. Since improved reproductive success is presumed to be a main benefit of maintaining a long-term pair bond, these results suggest a new avenue of research in the evolution of monogamy.

Correlation Between Live Weight and Carcass Weight and Giblet Weight In Broiler Chickens Given White Turmeric Extract

The objective of this research is to determine the correlation between live weight, carcass weight, and giblet weight in broiler chickens given 4% white turmeric extract. This study was conducted from July to September 2024 at the Poultry Unit of the Animal Husbandry Department, Faculty of Agriculture, Pattimura University Ambon. The materials used in this research were 60 Cobb strain broiler chickens. The feed provided consisted of BR1 and BR2 produced by PT. Malindo Feedmilk, vita stress, and Gumboro vaccine. The white turmeric extract administered was 40 ml from a total of 1000 ml of drinking water (4% white turmeric extract). The data analysis technique used in this study was simple linear regression statistical testing to examine the effect of the independent variable (live weight) on the dependent variable (carcass weight) of broiler chicken at a significance level (?) = 0.05. Data processing was performed using the SPSS computer program. The results showed that live weight had a very strong (0.992) and positive correlation with carcass weight in broiler chickens given 4% white turmeric extract, while live weight and giblet weight had a strong (0.711) and positive correlation