Hatch Weight Research Articles

Maternal low-protein diet programmes offspring growth in association with alterations in yolk leptin deposition and gene expression in yolk-sac membrane, hypothalamus and muscle of developing Langshan chicken embryos

The present study was aimed to investigate the mechanism underlying the influence of maternal low-protein (LP) diet on offspring growth in the chicken. One hundred and twenty Chinese inbred Langshan breeder hens were allocated randomly into two groups fed diets containing low (10%, LP) or normal (15%) crude protein levels. Low dietary protein did not affect the body weight of hens, but significantly decreased the laying rate and egg weight. The yolk leptin content was significantly lower in eggs laid by LP hens, while no differences were detected for yolk contents of corticosterone, tri-iodothyronine (T3) or thyroxine. Despite significantly lower hatch weight, the LP offspring demonstrated obviously higher serum T3 concentration, which is in accordance with the faster post-hatch growth rate achieving significantly heavier body weight and pectoralis major muscle weight 4 weeks post-hatching. Expression of 20-hydroxysteroid dehydrogenase (20-HSD) mRNA in the yolk-sac membrane was significantly down-regulated at embryonic day 14, whereas that of transthyretin and leptin receptor (LepR) was not altered. Moreover, hypothalamic expression of 20-HSD, glucocorticoid receptors, thyrotropin-releasing hormone and LepR mRNA was significantly up-regulated in the LP group compared with their control counterparts. In the pectoralis major muscle, significantly higher expression of insulin-like growth factor (IGF)-I and IGF-I receptor mRNA was observed in LP embryos. The present study provides evidence that maternal LP diet programmes post-hatch growth of the offspring. The associated alterations in yolk leptin deposition as well as in yolk-sac membrane, fetal hypothalamus and muscle gene expression may be involved in mediating such programming effect in the chicken.

Ação do fungo Beauveria bassiana associado a gel polimerizado de celulose no controle do carrapato Anocentor nitens em teste de campo

Foram selecionados 20 equídeos naturalmente infestados por Anocentor nitens, dos quais seus pavilhões auriculares foram submetidos a quatro tratamentos distintos: gel associado a Beauveria bassiana, apenas gel, apenas B. bassiana e um grupo-controle. Procederam-se à contagem e ao registro do número total de fêmeas adultas (>3mm) em cada pavilhão auricular, nos dias 0, 1, 4, 7, 11, 14, 18, 21, 25 e 28, para cálculo do percentual de controle. Foram coletadas e mantidas em laboratório 20 fêmeas pertencentes a cada tratamento, para cálculo dos períodos de pré-postura, postura, incubação e eclosão, e peso médio das posturas. No grupo tratado com o composto gel associado a B. bassiana, observou-se percentual de controle maior que 50%, entre o 4º e o 25º dia, assim como decréscimo progressivo do peso médio da postura das fêmeas coletadas no período entre o 7º e 14º dia. Para os outros tratamentos, o percentual de controle manteve-se abaixo de 20%, e o peso da postura não apresentou diferença significativa. Os percentuais de controle, assim como as reduções no peso médio da postura, sugerem que a utilização do composto gel associado a B. bassiana potencializou a virulência do entomopatógeno.

Efeitos de Fatores Ambientais na Reprodução de Tartarugas

Para as espécies de tartaruga que apresentam a determinação sexual dependente da temperatura da incubação o local e o momento da desova, exercem influências que vão além da definição do sexo dos embriões. A influência do local da desova se estende a todo o desenvolvimento embrionário afetando o comportamento e o tamanho dos filhotes. O momento em que ocorre a desova trará conseqüências ao ambiente térmico dos ninhos à medida que a temperatura e a umidade variam ao longo do ano. A umidade será decisiva nas trocas hídricas e gasosas entre os ovos e o meio afetando a absorção do vitelo e o crescimento dos embriões. As cheias e os alagamentos são importantes fatores de perda de ninhos nas espécies de tartaruga de água doce. A desova no momento adequado possibilita uma incubação segura, sem a interferência de alagamentos dos ninhos e conseqüente morte dos embriões. A predação dos ninhos varia de acordo com o local da desova, o tipo e a abundância de predadores e a profundidade da câmara de ovos. A escolha de pontos de desova no interior da vegetação, onde a taxa de predação é geralmente menor, nem sempre é a estratégia mais frequentemente adotada pelas tartarugas, uma vez que esse procedimento pode levar a uma maior exposição das fêmeas aos predadores, à diminuição do sucesso da eclosão ou a alterações na razão sexual provocadas por diferenças na temperatura da incubação.

Habitat-specific clutch size and cost of incubation in eiders reconsidered

The energetic incubation constraint hypothesis (EICH) for clutch size states that birds breeding in poor habitat may free up resources for future reproduction by laying a smaller clutch. The eider (Somateria mollissima) is considered a candidate for supporting this hypothesis. Clutch size is smaller in exposed nests, presumably because of faster heat loss and higher incubation cost, and, hence, smaller optimal clutch size. However, an alternative explanation is partial predation: the first egg(s) are left unattended and vulnerable to predation, which may disproportionately affect exposed nests, so clutch size may be underestimated. We experimentally investigated whether predation on first-laid eggs in eiders depends on nest cover. We then re-evaluated how nesting habitat affects clutch size and incubation costs based on long-term data, accounting for confounding effects between habitat and individual quality. We also experimentally assessed adult survival costs of nesting in sheltered nests. The risk of egg predation in experimental nests decreased with cover. Confounding between individual and habitat quality is unlikely, as clutch size was also smaller in open nests within individuals, and early and late breeders had similar nest cover characteristics. A trade-off between clutch and female safety may explain nest cover variation, as the risk of female capture by us, mimicking predation on adults, increased with nest cover. Nest habitat had no effect on female hatching weight or weight loss, while lower temperature during incubation had an unanticipated positive relationship with hatching weight. There were no indications of elevated costs of incubating larger clutches, while clutch size and colony size were positively correlated, a pattern not predicted by the 'energetic incubation constraint' hypothesis. Differential partial clutch predation thus offers the more parsimonious explanation for clutch size variation among habitats in eiders, highlighting the need for caution when analysing fecundity and associated life-history parameters when habitat-specific rates of clutch predation occur.

Estimativas da trajetória genética do crescimento de codornas de corte utilizando modelos de regressão aleatória

Avaliou-se a trajetória genética do crescimento de codornas de corte (pesos corporais nos dias 1, 7, 14, 21, 28, 35 e 42 de idade) de dois grupos genéticos, por modelos de regressão aleatória, sob modelo animal, obtendo-se estimativas de parâmetros genéticos visando definir a idade que resultaria em maior resposta à seleção. Foram pesadas 2.432 e 2.478 codornas, respectivamente, dos grupos genéticos EV1 e EV2, obtidas em três gerações de seleção. Os parâmetros genéticos foram estimados utilizando-se a sub-rotina Dxmrr do DFReml. As estimativas de herdabilidade dos pesos corporais variaram, respectivamente, de 0,01 a 0,50, para o grupo genético EV1, e de 0,01 a 0,10, para o EV2, sendo as maiores estimativas obtidas para peso corporal no 42º dia de idade, em ambos os grupos genéticos. As correlações genéticas entre o peso a um dia e os demais pesos corporais, em ambos os grupos, foram negativas, e as correlações de ambiente permanente, de modo geral, foram maiores para EV2. Pode-se concluir que, para ambos os grupos, a seleção é mais eficiente se realizada no 42º dia de idade, porém respostas poderiam ser obtidas se as codornas fossem selecionadas em idades mais jovens para o grupo EV1.

Single nucleotide polymorphism (SNP) at the GHR gene and its associations with chicken growth and fat deposition traits

1. The growth hormone receptor (GHR) plays crucial roles on chicken growth and metabolism. 2. The full cDNA of the chicken GHR gene was scanned for single nucleotide polymorphisms (SNP) by means of denaturing high-performance liquid chromatography (DHPLC). Three SNP, C6540334T, C6542011T and G6631778A, were genotyped in a F2 designed full-sib resource population to analyse their associations with chicken growth and fat deposition traits. 3. Fifty-five SNP and two other variations were identified in the 8908 bp region of the GHR gene. Among the 55 SNP, 10 were located in coding exons (6 resulted in changes of amino acids) and 45 were in non-coding regions (introns, 5′UTR and 3′UTR). The nucleotide diversity (θ), corrected for sample size of chicken GHR gene, is 1·45 × 10−3. Fourteen PCR-RFLP markers were developed in the chicken GHR gene. 4. The G6631778A was associated with body weight at 63 d (BW63), dressed weight (DW) and subcutaneous fat thickness (SFT), BW35 and BW49 (P < 0·01) as well as hatch weight (HW) and BW42 in the male population. However, G6631778A was only associated with BW28 in the female population. G rather than A was dominant for chicken growth and fat deposition. Haplotypes based on the three SNP were associated with BW21, BW70, BW77 and SFT, BW7, BW35, BW42, BW49 and BW56 in males, and associated with BW7 and BW14 in females. For growth in males, the H2 and H6 haplotypes had positive and negative effects, respectively; meanwhile H6 was predominant for fat deposition.

The PIT1 gene polymorphisms were associated with chicken growth traits

BackgroundWith crucial roles on the differentiation of anterior pituitary and the regulation of the prolactin (PRL), growth hormone (GH) and thyroid-stimulating hormone-β (TSH-β) genes, the chicken PIT1 gene is regarded as a key candidate gene for production traits. In this study, five reported polymorphisms (MR1-MR5) of the PIT1 gene were genotyped in a full sib F2 resource population to evaluate their effects on growth, carcass and fatty traits in chickens.ResultsMarker-trait association analyses showed that, MR1 was significantly associated with shank diameters (SD) at 84 days (P < 0.05), hatch weight (HW) and shank length (SL) at 84 days (P < 0.01), MR2 was significantly associated with BW at 28, 42 days and average daily gain (ADG) at 0–4 weeks (P < 0.05), and MR3 was significantly associated with ADG at 4–8 weeks (P < 0.05). MR4 was associated with SL at 63, 77, 84 days and BW at 84 days (P < 0.05), as well as SD at 77 days (P < 0.01). Significant association was also found of MR5 with BW at 21, 35 days and SD at 63 days (P < 0.05), BW at 28 days and ADG at 0–4 weeks (P < 0.01). Both T allele of MR4 and C allele of MR5 were advantageous for chicken growth. The PIT1 haplotypes were significantly associated with HW (P = 0.0252), BW at 28 days (P = 0.0390) and SD at 56 days (P = 0.0400). No significant association of single SNP and haplotypes with chicken carcass and fatty traits was found (P > 0.05).ConclusionOur study found that polymorphisms of PIT1 gene and their haplotypes were associated with chicken growth traits and not with carcass and fatty traits.

Relationships Among Egg Characteristics, Chick Measurements, and Early Growth Traits in Ten Broiler Breeder Strains

This study evaluated egg traits, yolk utilization, chick conformation, and early growth rate in 10 broiler breeder strains. The strains included pure-, specialized- and commercial-line products. The 210 eggs/strain were weighed and randomly designated to 1 of 3 experimental determinations: 8 eggs for measurement of eggshell conductance, 52 eggs for determination of egg characteristics, and 150 eggs for incubation and chick traits. Egg characteristics included egg weight, specific gravity, yolk weight, albumen weight, albumen height, eggshell weight, and eggshell thickness. Chick traits included navel condition, hock color, chick length, shank length, and abdomen score by manual palpation. At hatch, half the birds per strain were dissected to assess the weight of the yolk sac, heart, liver, and breast muscle. The remaining chicks were randomly distributed into 4 rearing pens for a 14-d assessment of growth rate. There was a 3-g range in egg weight among the strains. Eggs from a pure line had the greatest amount of yolk (22.6 g), with yolk weight ranging to a low of 20.9 g in 2 other strains. The male line strain and 2 female line strains had the highest hatching weights (46.3, 46.5, and 45.4 g, respectively), whereas a commercial strain had the lowest hatching weight (43.1 g). Egg size affected chick weight more than did yolk size. The residual yolk mass at hatch ranged from 5.50 g (in the male line) to 3.70 g in the commercial strains. Residual yolk mass accounted for approximately 10 to 14% of chick BW at hatch. The abdominal palpation score correlated with actual hatch residual yolk weight (r = 0.50; P < 0.0001). At hatch, differences in breast muscle and internal organ weight were present. Shank length at hatch correlated more strongly with 14-d BW (r = 0.39; P < 0.0001) than did hatch weight and 14-d BW (r = 0.35; P < 0.0001). The results of this trial demonstrated significant strain variation in internal organ weight, residual yolk sac mass, and chick carcass reserves, which, when added together, resulted in observable differences in chick weights across strains.

Effects of the estrogen agonist 17β‐estradiol and antagonist tamoxifen in a partial life‐cycle assay with zebrafish (Danio rerio)

A partial life-cycle assay (PLC) with zebrafish (Danio rerio) was conducted to identify endocrine-disrupting effects of 17beta-estradiol (E2) and tamoxifen (TMX) as reference for estrogen agonist and antagonist activity. Adult zebrafish were exposed for 21 d and offspring for another 42 d, allowing differentiation of gonads in control animals. The assessed end points included reproductive variables (egg production, fertilization, and hatching), gonad differentiation of juveniles, histopathology, and vitellogenin (VTG) expression. With E2, the most sensitive end points were feminization of offspring (at 0.1 nM) and increased VTG production in males (at 0.32 nM). At 1 nM, decreased F, survival, increased F, body length and weight, VTG-related edema and kidney lesions, and inhibited spermatogenesis were observed. Oocyte atresia occurred at even higher concentrations. Exposure to TMX resulted in specific effects at an intermediate test concentration (87 nM), including oocyte atresia with granulosa cell transformation and disturbed spermatogenesis (asynchrony within cysts). In F1, decreased hatching, survival, and body weight and length as well as decreased feminization were observed. Decreased vitellogenesis and egg production in females and clustering of Leydig cells in males occurred at higher concentrations. Toxicological profiles of estrogen agonists and antagonists are complex and specific; a valid and refined characterization of endocrine activity of field samples therefore can be obtained only by using a varied set of end points, including histology, as applied in the presented PLC. Evaluation of only a single end point can easily produce under- or overestimation of the actual hazard.

Effects of Electric Field During Incubation of Eggs on the Hatchability and Post-Hatch Performance of Meat Chickens

The effects of electric field (EF) during incubation of eggs on hatchability traits, and post-hatch performance, nutrient utilization and carcass characteristics of meat chickens were investigated in 2 trials. Eggs from a meat-type breeder flock were incubated under EF of 30kV/m, 60Hz during the first 18 d of incubation as compared with the control incubation treatment (C). Chicks hatched from the two incubation treatments (EF and C) were fed ad libitum and their performance was monitored. Measurements were made of hatchability, hatchability failures, chick hatching weight (CHWT), length of incubation, post-hatch performance (weight gain (WTG), feed consumption, and feed conversion ratio (FCR)), and nutrient utilization (apparent nitrogen retention and nitrogen corrected metabolizable energy of birds at 30 d of age), and carcass characteristics of sexed birds at 40 d of age. EF incubation of eggs significantly (P < 0.05) increased per cent of hatchability, per cent of hatching chicks by 468 hour of incubation, CHWT and reduced embryo deaths, pips with life embryos, length of incubation and percentage of hatched chicks at 492 plus 504 of incubation by approximately 11.0, 428, 2.4, 56, 86, 5.1 and 98%, respectively. EF birds had a higher (P < 0.05) WTG than the C birds, when they were placed with feed and water after hatching, but not when birds were held without feed and water to the end of incubation period. EF incubation of eggs did not significantly influenced feed intake, FCR, and nutrient utilization of birds. Carcass of the EF birds had higher (P < 0.01) proportion of drumstick (g/kg eviscerated carcass (EC)), and lower proportions of edible offal (liver plus heart plus gizzard, g/kg live weight (LWT) and thigh (g/kg EC) when compared with those of the C birds. Carcass of male birds had significantly (P < 0.01) higher proportion of drumstick (g/kg EC), and lower proportion of edible offal (g/kg LWT) than female birds. In the EF group, female birds had significantly (P < 0.01) higher LWT and carcass neck plus back (g/kg EC), and lower EC (g/kg LWT) and carcass breast (g/kg EC) than males birds. However in the C group, male birds had a higher LWT than female birds. Whilst, sex of birds of the C group did not significantly influence EC (g/kg LWT), and carcass breast and back plus neck (g/kg EC). It is concluded that the incubation of eggs under EF of 30kV/m, 60Hz increased hatchability of eggs, and chick hatching weight, reduced incubation time of eggs and altered carcass characteristics of birds. EF incubation of eggs increased weight gain of birds when hatched chicks were placed with feed and water after hatching. EF incubation of eggs did not altered feed efficiency, and nutrient utilization of meat chickens.

Relationship Between Chick Conformation and Quality Measures with Early Growth Traits in Males of Eight Selected Pure or Commercial Broiler Breeder Strains

Current commercial broiler products are derived from the crosses of various strains at the primary breeder level. This study investigated chick development, yolk utilization, and early growth rate of males from 8 broiler breeder strains. These strains were a combination of both specialized and commercial-line products. At hatch, 110 male chicks per strain were weighed and wing-banded, and chick quality was assessed. Traits included navel condition, hock color, chick length, shank length, and abdomen score by abdominal palpation (to evaluate residual yolk content on live chicks). At hatch, 50 chicks per strain were dissected to assess breast muscling and residual yolk weight. At 2 wk of age, 50 chicks per strain were dissected to characterize changes in weight, conformation, fleshing, and residual yolk content. Chick weight at hatch varied from 40.8 g in a heavily growth-selected line to a low of 36.9 g in a commercial strain. The mass of residual yolk at hatch ranged from 0.8 to 10.6 g across all chicks dissected at hatch. A heavily breast-selected pure-line strain had 5.8 g of residual yolk in contrast to the commercial strain that had only 3.0 g. Although there were no significant strain differences in abdomen score, this score correlated with dissected residual yolk weight (r = 0.50). Shank length and chick body length at hatch correlated more strongly with BW on d 14 than did hatch weight. This information stresses the importance of evaluating several characteristics at hatch to better quantify early chick quality.

Maternal antibodies in a wild altricial bird: effects on offspring immunity, growth and survival

1. In many animals immunity is not fully developed until adulthood but the young still need protection against various sets of pathogens. Thus, bird nestlings are highly dependent on antibodies received from their mother (in the eggs) during their rapid early growth period. The relationship between maternal immunity and the development of neonates' own immunity has been poorly studied. 2. It has been suggested that immune function plays an important part in mediating resource competition between different life-history traits, e.g. growth and reproduction. Maternal investment of antibodies has potentially permanent effects on offspring phenotype. Thus, the trade-offs between the immune function and other important life-history traits in the offspring will also affect the fitness of the mother. 3. Our supplemental feeding experiment in the magpie Pica pica indicates that the immunoglobulin levels of offspring at hatching are dependent on a mother's nutritional condition. In addition, the amount of maternal immunoglobulins transferred to offspring increases along the laying order within a nest. 4. We also found that at the age of 8-10 days the immunoglobulin production of the offspring has already begun. Furthermore, the maternal immunoglobulin levels of the offspring at hatching were positively related to their immunoglobulin levels on day 10. 5. Maternal immunoglobulins did not significantly affect offspring growth, but there was a negative relationship between self-produced immunoglobulins and growth over the first 10 days, indicating a trade-off between these traits. Nestlings' weight, however, had a positive relationship with immunoglobulin production suggesting that the observed trade-off between growth and immunoglobulin production is due to catch-up growth of nestlings with a low hatching weight. We found that within nests nestlings with higher maternal antibody levels had higher survival rate until day 20, but between nests there was an opposite relationship. 6. Evidently, there is a trade-off, in magpies, between maternal resources, immune function and growth, shaping the evolution of maternal investment in offspring immunity.

Association of Single Nucleotide Polymorphisms of the Insulin Gene with Chicken Early Growth and Fat Deposition

Growth rate, body composition, and fat deposition are important traits in chickens. Insulin plays important roles in hepatic cells, muscle cells, and adipose tissue cells. The purpose of the present study was to analyze association of the insulin (INS) gene with chicken growth and body composition traits. Using a F2 design resource population constructed with the crossing of Chinese native Xinghua chickens and White Recessive Rock chickens, the association of 4 single nucleotide polymorphisms (SNP; A+428G, C+1549T, T+3737C, and A+3971G) of INS gene with 13 growth and body composition traits was studied. The T+3737C genotypes were significantly associated with small intestine length (P = 0.0002), and the A+3971G genotypes were significantly associated with early growth (hatch weight and BW at 28 d of age) (P < 0.0001), breast angle (P = 0.0002), and small intestine length (P < 0.0001). None of the 4 SNP was significantly associated with abdominal fat pad weight (P > 0.05). The haplotypes based on the 4 SNP were also significantly associated with early growth (hatch weight and BW at 28 d of age; P < 0.0001) and breast angle (P < 0.0001) but not with small intestine length (P = 0.0505). These results suggested that variation of the insulin gene was significantly associated with chicken early growth but not with fat deposition. In addition, the data from the present study supported the inference that both the one-SNP-at-a-time and the haplotype-based approaches have their own advantages and disadvantages when association analysis of one SNP and haplotypes with chicken complex traits was conducted.

An 8 bp indel in exon 1 of Ghrelin gene associated with chicken growth

Ghrelin, acts as the endogenous ligand for growth hormone secretagogues receptor (GHS-R), is a novel growth hormone (GH) releasing peptide with reported effects on food intake in chickens. In this study, an 8 bp indel polymorphism in exon 1 of the chicken Ghrelin ( cGHRL) gene was genotyped in a F 2 designed full-sib population to analyze its associations with chicken growth and carcass traits. Later, mRNA level in the proventriculus was determined by real-time PCR to reveal the expression feature of cGHRL gene. Result showed that this 8 bp indel was significantly associated with body weight at the age of 28 days (BW28) and 56 days (BW56), eviscerated weight (EW) and leg muscle weight (LMW) ( P < 0.05), highly significantly associated with hatch weight (HW), BW14, 21, 35, 42, 49, 90 and body length (BL), dressed weight (DW), eviscerated weight with giblet (EWG), wing weight (WW), breast muscle weight (BMW) and head and neck weight (HNW) ( P < 0.01). Meanwhile, A allele (with ‘CTAACCTG’) was positive for chicken growth as individuals with AA genotype had the highest value of all traits. Analysis on cGhrelin mRNA level revealed that it differed significantly among individuals with three genotypes ( P < 0.05). Individuals with AB genotype had the highest mRNA level, whereas that of AA had the lowest one. It was concluded that this 8 bp indel of cGHRL gene was significantly associated with most body weight and body composition traits, and negative effect of endogenous Ghrelin on chicken growth were indicated by this study.

Effects of injected gluconeogenic supplementation on the performance of broilers from young breeders

Previous research has shown that administering carbohydrates to late-term embryos increases chick hatching weight and liver glycogen content and that supplementing broiler chicks from young hens at day of hatch with subcutaneously injected hydrolyzed casein and thiamine enhances their early performance. It was hypothesized that other practical and readily available gluconeogenic energy sources, including hydrolyzed casein, may similarly be given to hatchlings from immature breeder hens to increase the availability of liver glycogen reserves and augment growth. In addition to physiological saline (sham) and hydrolyzed casein treatments, 2 other treatments containing practical gluconeogenic energy sources (chicken egg crude albumin or albumin hydrolysate) were tested in the current study using hatchlings that were subsequently provided adequate brooding and nutrition. Added biotin was included in the crude albumin treatment. There were no treatment effects on mortality, BW gain, feed or water consumption, feed conversion, body temperature, hematocrit, plasma refractive index, relative liver weight, or liver glycogen content at any of the ages or age intervals examined through d 16 posthatch. These results suggest that under proper brooding conditions and timely feed provision, growth is not facilitated by injected casein hydrolysate, chicken egg crude albumin, or chicken egg albumin hydrolysate during the early transition from fat to carbohydrate-based nutrient uptake in posthatch chicks from young breeder hens.

Intraclutch Egg-Size Variation in Magellanic Penguins

Abstract We investigated patterns and consequences of intraclutch egg-size variation in Magellanic Penguins (Spheniscus magellanicus). First-laid eggs were significantly larger than second-laid eggs, although the mean difference represented only 2% of an average egg's volume. The degree of intraclutch egg-size variation was similar among years and females of different ages. Intraclutch egg-size variation did not affect intraclutch differences in chick hatching weights or fledging success. We found no selective advantage for laying eggs of different sizes. Because both eggs have an equal probability of being lost, chance favors equal provisioning of eggs. Egg volume explained 35% of the variation in hatching weight but did not determine fledging success. Laying order, year, and female age were better predictors of fledging success than egg size. Factors such as laying and hatching order, parental quality, oceanographic conditions, fights, and predation are more important in determining chick survival than are differences in egg size.

In ovo feeding improves energy status of late-term chicken embryos

Maintenance of glucose homeostasis during late-term embryonic development is dependent upon the amount of glucose held in reserve primarily in the form of glycogen in the liver and upon the degree of glucose generated by gluconeogenesis from protein first mobilized from amnion albumen and then from muscle. Insufficient glycogen and albumen will force the embryo to mobilize more muscle protein toward gluconeogenesis, thus restricting growth of the late-term embryo and hatchling. We hypothesize that administration of available carbohydrates to the amnion will improve glycogen reserves and spare muscle protein mobilization for gluconeogenesis during late-term embryonic and posthatch neonatal development. Our hypothesis was tested by comparing BW gain, liver glycogen reserves, and muscle weight of in ovo fed and control embryos during last days of embryonic incubation until 25 d after hatching. We examined, using 600 birds from 2 different strains of commercial boilers, body and muscle weights and glycogen reserves following feeding embryos at d 17.5 of incubation with a solution containing maltose, sucrose, dextrin, and β-hydroxy-β-methylbutyrate (HMB). Providing carbohydrates and HMB to late-term embryos increased hatching weights by 5 to 6% over controls, improved liver glycogen by 2- to 5-fold, and elevated relative breast muscle size by 6 to 8%. These weight advantages were sustained through the end of the experiments at 25 d of age. It is reasonable to assume that the elevated glycogen levels in the in ovo treatment reduce the need to produce glucose via gluconeogenesis and, therefore, contribute to less use of muscle protein and hence a greater percentage of pectoral muscle weight in the in ovo birds.

Effect of intensity of eggshell pigment and illuminated incubation on hatchability of brown eggs

1. The effects of intensity of brown eggshell pigment (light (LBP), medium (MBP) and dark (DBP)) and light intensity during incubation (low and high, 900 to 1380 and 1430 to 2080 lux, respectively) on eggshell characteristics, embryonic growth, hatchability traits, chick hatching weight and hatching time were investigated using eggs from a meat-type breeder (Hybro) flock at 32, 36 and 41 weeks of age in three trials. 2. With eggs of similar weights the intensity of brown pigment was not associated with eggshell weight and thickness, and did not influence embryo weight and egg weight loss during incubation. 3. The shade of brown pigment of eggs laid by young hens influenced the percentage hatchability (HP) of eggs incubated under light. Illuminated incubation improved HP of LBP eggs (compared with MBP and DBP eggs) from 32- and 36-week-old hens, but had no significant effect on HP of eggs from 41-week-old hens. 4. Light intensity during incubation did not influence egg weight loss. High intensity of light during incubation reduced HP and increased early death percentage (EDP) in the LBP and MBP groups, and did not influence HP and EDP in the DBP group. 5. Brown eggshell pigment and intensity of light during incubation did not influence hatching time. 6. It is concluded that the shade of brown pigment, intensity of light during incubation and age of the breeder hens influenced the hatchability performance of embryos from brown eggs. Light during incubation improved the hatchability of embryos in light brown eggs laid by young hens and the shade of brown pigment of eggs laid by older hens did not influence hatchability under illuminated incubation. 7. High intensity of light during incubation reduced hatchability of light and medium brown eggs, but not the dark brown eggs.

Indigenous chicken genetic resources in Bangladesh: current status and future outlook

SummaryLivestock, especially poultry, is a promising sector for poverty reduction in Bangladesh. Approximately 140 millions chickens are scattered throughout 68 000 villages in the country, mostly of indigenous, non-descript type. The production system for indigenous chickens is smallholder backyard scavenging in nature with each family keeping an average of 6–7 chickens to meet family requirements, and from which a cash income can also be derived when necessary. Indigenous chickens produce about 75% of the eggs and 78% of the meat consumed domestically. Among said indigenous chicken genetic resources, non-descript Deshi, Aseel and Naked Neck breeds are noteworthyThe non-descript Deshi chicken constitutes about 90% of the indigenous population. Also known as ‘Murghi’, they have undergone unknown periods of natural selection and are a reservoir of excellent genetic diversity. They show high levels of morphological and phenotypic variability and increased fitness under natural settings. Studies reveal that they may be regarded as one breed or population because of the small genetic distances among them. Deshi chickens are characterized by black (75%) and red (25%) plumage colour; black (39%), yellow (32%) and white (29%) shank color; black (99%) eye color; bright red (59%) and pale (41%) comb colour; white (82%) and yellow (17%) skin colour; no definite (61%) and lacing (17%) feather pattern; medium (70%) and large (19%) body size; single comb (97%) and rudimentary spur (98%); medium egg size (80%); light brown (67%) and white (27%) egg shell colour. Regarding production traits, Deshi chickens have average hatch weight of 29 g; body weight at 4, 8, 12 weeks; weekly weight gain (0–12 weeks) of respectively of 77, 175, 315, 24 grams; age at first egg (175 days); weight of pullet (0.9 kg); mature body weight (1.3 kg); hatchability (52%); fertility (83%); annual egg production (45 -50 eggs); 9% mortality up to 500 days of age.The indigenous chicken population of Bangladesh has been undergoing genetic erosion since the 1960s, following the introduction of improved stock from developed countries. Efforts to sustain commercial hybrid broiler and layer chicken farming under intensive and semi-intensive production models have been tested, but efficiency of systematic characterization, screening, breed improvement and conservation programmes with the indigenous Deshi chickens at the smallholder village levels (in-situ) of Bangladesh are yet to be tested. Such an initiative may help to save these creatures from the grip of thethreat of extinction. This in turn may help to sustain village chicken production system in Bangladesh and could be a useful micro-economic strategy in the on-going poverty alleviation process in the country.

Growth and survival of neotropic cormorant (Phalacrocorax brasilianus) chicks in relation to hatching order and brood size

We investigated chick development and feeding rate in the neotropic cormorant, Phalacrocorax brasilianus, in a colony in Central Chile. The year of our study was characterized by relatively good foraging conditions. Brood sizes varied from two to five chicks, and hatching was asynchronous, with gaps of 0 to 6 days between the youngest and the oldest chick. Egg size declined over laying order in three-egg clutches, but not in four-egg clutches. Hatch weight did not vary with hatching position, irrespective of brood size. Chicks increased mass on average by 60 g/day between 8 and 20 days of age. Growth rates and survival to fledging depended on hatching position only in broods of four, where D-chicks grew slower and showed a higher pre-fledging mortality. There was a non-significant tendency that also A-, B-, and C-chicks in broods of four grew slower than in smaller broods. Average number of fledglings was 2.76. Feeding frequency decreased with chick age between the ages of 10–40 days. Four-chick broods received more feeds per day than smaller broods, leading to a similar per-chick feeding frequency across all brood sizes. D-chicks were clearly disadvantaged in growth and survival, and facultative brood reduction occurred.