Breeder Hens Research Articles

TGF-β4 and HSP70 responses in breeder hens treated with thyroxine

A hypothesis was tested that long-term administration of thyroxine (T4) in broiler breeder hens would affect fertility, sperm penetration rate, and the duration of fertility. Relative abundance of oviductal TGF-β4 and HSP70 mRNA was determined to ascertain whether T4 treatment affected these genes, and modulated the sustained storage of spermatozoa within the uterovaginal sperm storage tubules of hens. A total of 70, 47-week-old Cobb 500 breeder hens was randomly allotted to two treatment groups (T4 treatment (ET) and control). The T4 was orally administered to the ET group (0.3 mg T4/bird/day) for 100 consecutive days; whereas the control group was not administered T4 during the experimental period. Breeder hens were artificially inseminated to evaluate specific reproductive variables. On the last day of the treatment period two hens /replicate were randomly killed to estimate oviductal gene expression. The T4 treatment resulted in an increase in plasma concentration of T4; however, the T3 concentration was not affected. The long term administration of T4 had no effect on fertility; however, it resulted in a decreased sperm penetration rate and decreased the duration of fertility compared with the control group. The relative abundance of TGF-β4 and HSP70 mRNA in the SST was not influenced by T4 supplementation. The correlation coefficients between fertility and sperm penetration rate with relative abundance of TGF-β4 and HSP70 were not significant. Overall, among the diverse reproductive variable assessed in the current study, the sperm penetration rate and the duration of fertility were most responsive to long-term treatment with T4.

Effect of housing system on egg quality and the concentration of cholesterol in egg yolk and blood of hens of native resources of the Czech Republic and Slovakia

SUMMARY The effect of the housing system on egg production, quality, and the concentration of egg yolk and blood serum cholesterol was studied in hens from the genetic resources available in the Czech Republic and Slovakia. A total of 132 pullets was divided according to breed (Czech hens x Oravka hens) and the housing system (36 hens per enriched cage and 30 hens per litter). The eggs for the laboratory evaluation were collected over 2 consecutive d during 4-week periods. Significant interactions between breed and housing system were found in some egg quality parameters (with the exception of egg weight). Higher albumen and yolk quality were found in Oravka hens on litter, but higher eggshell quality was detected in Czech hens on litter. The cholesterol concentration in egg yolk was significantly affected by the breed and housing system of hens. A significantly higher average concentration of cholesterol in egg yolk was in Oravka hens (11.22 mg/g) and in layers housed on litter (11.24 mg/g). The influence of the housing system and interaction between the breed and housing system on cholesterol concentration in blood serum were significantly different. The highest concentration of cholesterol in blood serum was in Oravka hens in cages (3.65 mmol/l). The results show that the selection of a suitable genotype and housing system can affect egg quality and the concentration of cholesterol in egg yolk.

Short periods of incubation, egg turning during storage and broiler breeder hens age for early development of embryos, hatching results, chicks quality and juvenile growth

An effect of modification of storage conditions of the eggs of broiler breeder flocks at the age of 49-, 52- and 70-, 73-wks of life on an early embryonic development, hatching time and synchronization, hatchability rates, chicks quality and broiler growth was investigated. The eggs were divided into 4 experimental groups: COI = eggs storage 5 d, at turning every 12h; NSP = eggs storage 12 d, at turning every 12h; SPIDES = were treated with 4h pre-incubation at 30°C and 50-55% air humidity, delivered at 5 and 10 d over of 12 d of storage, and turning every 12h; NCOI = eggs storage 12 d, no turning and no pre-incubation. Eggs from older hens were characterized by poorer hatchability and poorer chicks quality. The use of 2 × 4h pre-incubation in 12 d of eggs storage could have an effect on the initial acceleration of embryonic development in eggs of young hens, contributing to the alignment of embryos development in eggs from young and older hens to 72h of incubation. Pre-incubation had no effect on the length of incubation period, hatching window, but it increased the hatchability of the set and apparently fertilized eggs and decreased the number of eggs not hatched, and also improved chicks quality. Eggs turning by 90° every 12h during the storage positively affected the embryonic development, shortening the incubation time and the quality of chicks, but had no effect on hatchability rates and body weight in 42 d of life. Based on the obtained results, it can be concluded that the applied modifications can be effective in counteracting the negative effects of storage of hatching eggs from both young and older birds.

The effect of rearing photoperiod on broiler breeder reproductive performance depended on body weight

ABSTRACTBody weight (BW) and rearing photoperiod are important factors affecting sexual maturation rate and reproductive performance in broiler breeders. The current experiment used a 2 × 3 factorial arrangement of treatments to study the interaction between BW and rearing photoperiod on reproductive performance in group housed broiler breeder hens, while minimizing variation in BW. Hens (n = 180) were fed with a precision feeding system to allocate feed individually to achieve the breeder-recommended target curve (Standard) or to a target curve that reached the 21 wk BW at 18 wk (High). Hens were on 8L:16D, 10L:14D, or 12L:12D photoschedules during rearing and were photostimulated at 21 wk with a 16L:8D photoschedule. Sexual maturity (defined as age at first egg) and individual egg production to 55 wk were recorded. At 55 wk, proportional weights of individual body components were determined by dissection. Differences were reported as significant at P ≤ 0.05. A significant interaction between BW and rearing photoschedule affected age at sexual maturity and egg production. In the High BW treatment, age at sexual maturity did not differ between hens under the 8L:16D and 10L:14D photoschedules (173 vs. 172 d, respectively). In the Standard BW treatment, the 12L:12D rearing photoperiod delayed sexual maturity compared with the 8L:16D rearing photoperiod (266 vs. 180 d, respectively). All hens on the High BW treatment laid at least 1 egg before the end of the experiment. Conversely, 3.3, 18.1, and 37.6% of Standard BW hens on the 8L:16D, 10L:14D, and 12L:12D photoschedules, respectively, never commenced egg production. At the end of the experiment, proportional breast weight was higher and proportional fatpad weight was lower in Standard compared to High BW hens (25.8 vs. 27.5% and 2.4 vs. 1.5% of BW, respectively). We conclude that increased BW partially counters the effect of longer photoschedules on sexual maturity in broiler breeders and that dissipation of the photorefractory state depends on BW.

Polymorphism detection of promoter region of IFN- $$\gamma $$ γ and IL-2 genes and their association with productive traits in Mazandaran native breeder fowls

To identify polymorphism in interferon gamma (IFN-γ) and interleukin-2 (IL-2) genes, blood samples were collected from 380 breeder hens of the Mazandaran native fowls breeding station. DNA extraction was performed through a modified saltingout method and fragments of 670 and 659 bp from the promoter regions of IFN-γ and IL-2 genes were amplified by using specific primers, respectively. Following genotyping in the IFN-γ gene using the Tsp509I restriction enzyme, two alleles of A and G with the frequencies of 0.55 and 0.45 and three genotypes of AA, AG and GG were observed with the frequencies of 0.32, 0.46 and 0.22, respectively. For the IL-2 gene, two alleles of A and G were also detected using the MnlI restriction enzyme with the frequencies of 0.58 and 0.42 and three genotypes of AA, AG and GG with the frequencies of 0.33, 0.50 and 0.17, respectively. Statistical analysis revealed significant associations between IL-2 gene single-nucleotide polymorphism and productive traits including the average egg weight (EW) at 345-375 days of age, egg number (EN) at 345-375 days of age and body weight (BW) at 8weeks of age traits (P<0.05). Further, in a mean comparison analysis, there were also significant differences between different genotypes of the IL-2 gene in average EWat 28 and 30weeks of age, in which AG genotypes showed higher performance. Additionally, for the IFN-γ gene, a significant difference was found between the genotypes in average EW at 28 weeks of age trait. Therefore, it can be concluded that the above-mentioned polymorphisms could be considered as the pivotal geneticmakers to improveMazandaran native fowl breeding programmes to achieve the optimum performance in productive traits more efficiently.

Characterization of the novel genotype avian hepatitis E viruses from outbreaks of hepatic rupture haemorrhage syndrome in different geographical regions of China.

Since 2016, hepatic rupture haemorrhage syndrome (HRHS) has emerged in layer and broiler breeder hens in several provinces of China, and novel genotype avian hepatitis E viruses were detected from these chickens. To gain a better understanding of the genetic properties of the novel avian HEV strain, the capsid gene of four isolates from birds at four farms experiencing HRHS in different geographical regions were determined and compared with those of reported pathogenic and nonpathogenic avian HEV isolates as well as mammalian HEVs. Results showed that all those isolates share 80.1%-88.2% nucleotide sequence identity and 89.3%-91.9% amino acid sequence identity with other published avian HEV strains, while phylogenetic analysis further demonstrate that a novel genotype avian HEV was epidemic in China. Meanwhile, sequence analysis revealed that those novel isolates contain various amino acid mutations and even a hypervariable region in their major antigenic domains, which might be the critical factors for the pathogenicity elevation and even change their antigenicity. The data presented in this report will enhance the current understanding of the epidemiology and genetic diversity of the novel genotype avian HEV in China and provide additional insight into the critical factors that determine the pathogenicity of it.

Effect of Alternative Housing System and Hen Genotype on Egg Quality Characteristics

The aim of the study was to determine the effect of type of alternative housing system and layer genotype on the quality of table eggs. The investigated eggs came from native Greenleg Partridge hens (Z-11) and Rhode Island Red hens (R-11) covered by the gene-pool protection program, as well as from Hy-line Brown commercial hens from litter barn (LS), free range (FR), and organic systems (OS). Eggs for the study were collected from the hens at 56 wk of age. Egg quality assessment was based on the following values egg traits: weight, shape index, yolk, albumen, and shell percentage in the whole egg; eggshell traits: color intensity, weight, thickness, density, breaking strength, physical features of egg content: albumen height, value of Haugh units, yolk color; presence of meat/ blood spots and cholesterol, higher fatty acids, vitamin A and E in egg yolks. In the rearing systems under study, eggs with the highest weight were laid by commercial hens, and the type of alternative rearing system had no significant effect on this trait. Shell colour intensity depends on the breed of hen, whereas the rearing system has no significant effect on this trait. Hen genotype and housing system had an effect on egg shell weight, thickness, and density. The housing system influences the content of MUFA, PUFA, PUFAn-6 and PUFAn-3 as well as PUFA 6/3 in egg yolks. No effect of the housing system on egg yolk cholesterol content was observed.

Calcium particle size effects on plasma, excreta, and urinary Ca and P changes in broiler breeder hens.

An experiment was conducted using non-colostomized and colostomized broiler breeder hens to determine the effects of feeding limestone of 2 different mean particle sizes (185 microns and 3490 microns) on P excretion, total P and Ca retention, and urinary P and Ca excretion during a 6-week feeding study. Additionally, changes in plasma inorganic P (iP) and ionic Ca (Ca++) and urinary excretion of P and Ca were determined in one egg laying cycle of 24hours. One-hundred-fifty non-colostomized and 6 colostomized broiler breeder hens, 30 wk of age, were divided into 2 groups and fed broiler breeder diets supplemented with either small particle or large particle limestone. Two % acid insoluble ash (Celite) was added to the feed as a marker. Diets, excreta, and urine samples were analyzed for total P and Ca by ionic coupling plasma (ICP) analysis. The non-colostomized breeders fed large particle limestone compared to small limestone particles produced a significant increase in percent tibia ash (P < 0.0001) and egg specific gravity (P = 0.0382), but P excretion approached a tendency of being reduced (P = 0.1585). The urinary total P and Ca (∼18 and 9%, respectively) of total P and Ca excretion for breeders fed both sizes of limestone was not significantly different in the colostomized breeders. In plasma, both iP and Ca++ reached a peak during 18 to 20h and 20 to 24h post oviposition for smaller and larger particle sized limestone fed groups, respectively. The maximal excretion of urinary P was found during 11 to 20h post oviposition, whereas urinary Ca peaked during 0 to 11h post oviposition for both smaller and larger particle sized limestone supplemented groups. In summary, the findings indicate that the particle size (smaller and larger) of calcium source did not significantly influence the quantitative total urinary excretion of Ca and P but did influence the timing of Ca and P excretion.

Dynamics of nutrient utilization, heat production, and body composition in broiler breeder hens during egg production.

Changes in heat production (HP) and body composition (BC) in modern broiler breeders can provide means to understand nutrient utilization. Twelve Cobb 500 breeders were evaluated 10 times from 26 to 59 wk of age. The same wired caged breeders were moved to respiratory chambers connected to an indirect calorimetry to obtain oxygen consumption (VO2) and carbon dioxide production (VCO2), HP, and respiratory exchange ratio (RER). The same hens were evaluated for BC using a dual X-ray absorptiometry (DEXA). Data were analyzed during light (16h) and dark (8h) period using a mixed model to evaluate calorimetry parameters, a factorial design 2 × 10 for normalized calorimetry parameters, and Complete Randomized Design (CRD)-one way ANOVA for BC. Means were separated by Tukey-Honest Significant difference (HSD). HP increased with age (d) in 0.152kcal/d, VO2 and VCO2 were 0.031 and 0.024L/d per each increase in age (d), respectively. In the light period, hens consumed +17.4L/d VO2 and produced +18.9L/d VCO2 (P < 0.01). HP during the dark period was 84kcal/kg0.75 and during the light period was 115kcal/kg0.75. RER decreased with age until 43 wk and remained the same until 59 wk suggesting more fat and/or protein being oxidized at later periods of production. Lean body mass ranged from 642 to 783g/kg during the whole study reaching the lowest at 37 and 50 wk and the highest at 26 to 33 wk (P < 0.01). Body fat ranged from 168 to 261g/kg with the lowest at 26 to 33 wk and the highest at 50 wk of age (P < 0.01). Broiler breeder females may be catabolizing fat energy reserves from 50 wk onwards when the egg production is reduced, and HP increased at 54 and 59 wk (P < 0.01) due to higher energy required for maintenance of a higher lean mass structure. Broiler breeders change nutrient fuel use during egg production. Indirect calorimetry and DEXA can be used to pursue further feed strategies to maximize egg production and maintain a healthy breeder.

Copper requirements of broiler breeder hens.

One-hundred-twenty Cobb 500 hens, 20 wk of age, were randomly allocated into individual cages with the objective of estimating Cu requirements. After being fed a Cu deficient diet for 4 wk, hens were fed diets with graded increments of supplemental Cu (0.0; 3.5; 7.0; 10.5; 14; and 17.5ppm) from Cu sulfate (CuSO4 5H2O), totaling 2.67; 5.82; 9.38; 12.92; 16.83; and 20.19ppm analyzed Cu in feeds for 20 weeks. Estimations of Cu requirements were done using exponential asymptotic (EA), broken line quadratic (BLQ), and quadratic polynomial (QP) models. Obtained Cu requirements for hen d egg production and total settable eggs per hen were 6.2, 7.3, and 12.9ppm and 8.1, 9.0, and 13.4ppm, respectively, using EA, BLQ, and QP models. The QP model was the only one having a fit for total eggs per hen with 13.1ppm Cu as a requirement. Hemoglobin, hematocrit, and serum Cu from hens had requirements estimated as 13.9, 11.3, and 18.5,ppm; 14.6, 13.0, and 19.0ppm; and 16.2, 14.6, and 14.2ppm, respectively, for EA, BLQ, and QP models. Hatching chick hemoglobin was not affected by dietary Cu, whereas requirements estimated for hatching chick hematocrit and body weight and length were 10.2, 12.3, and 13.3ppm using EA, BLQ, and QP models; and 6.8 and 7.1ppm, and 12.9 and 13.9ppm Cu using EA and BLQ models, respectively. Maximum responses for egg weight, yolk Cu content, and eggshell membrane thickness were 14.9, 12.7, and 15.1ppm; 15.0, 16.3, and 15.7ppm; and 7.3, 7.8, and 14.0ppm Cu, respectively, for EA, BLQ, and QP models. Yolk and albumen percentage were adjusted only with the QP model and had requirements estimated at 11.0ppm and 11.3ppm, respectively, whereas eggshell mammillary layer was maximized with 10.6, 10.1, and 14.4ppm Cu using EA, BLQ, and QP models, respectively. The average of all Cu requirement estimates obtained in the present study was 12.5ppm Cu.

Effects of genotype and sterilization of chickens on growth rate, slaughter yield, whole poultry colour and physicochemical properties of poularde meat obtained from a hybrid breed of conservative chickens and meat roosters

Abstract The aim of the study was to determine the effects of genotype and sterilization on growth rate, carcass and meat quality. The subject of the study included hybrids obtained by crossing Ross 308 meat roosters with hens included in the genetic resource protection program in Poland, i.e. Yellow-Legged Partridge (Ż-33), Rhode Island Red (R-11) and Sussex (S-66). 8-week-old birds of each genetic group, i.e. ♂Ross 308x ♀Ż-33, ♂Ross 308 × ♀R-11, and ♂Ross 308x ♀S-66, were equally divided into pullets (K, control) and poulardes (P, experimental group). The sterilization procedure was performed in the 9 th week of life. The birds were fed ad libitum with whole-portion starter- and grower diets, and finisher mixes with 2% powdered whey addition. Beginning from the 11 th week, outdoor access was provided. The raising was completed in the 18 th week. The slaughter and meat quality assessment were performed based on 6 pieces from each group. It was found that poulardes obtained by crossing domestic general-purpose hen breeds with Ross 308 roosters achieved a slightly higher body mass, yet significantly higher content of pectoral muscles and deposit fat in the whole poultry, compared to pullets. Poularde whole birds were distinguished by higher colour saturation towards yellow, and pectoral muscles were lighter compared to pullets. Poularde meat was more tender and obtained better sensory evaluation results. The influence of hen genotype was noted in the case of body mass, musculature, whole poultry fat content and colour, as well as meat tenderness.

Comparison of single- and multi-strain probiotics effects on broiler breeder performance, egg production, egg quality and hatchability

ABSTRACT1. This study was conducted to investigate the effect of multi-strain probiotic (containing Lactobacillus acidophilus 2.5 × 107 cfu/g, Lactobacillus casei 2.5 × 107 cfu/g, Bifidobacterium thermophilum 2.5 × 107 cfu/g and Enterococcus faecium 2.5 × 107 cfu/g) and single-strain probiotic (Pediococcus acidilactici 1 × 1010 cfu/g) on broiler breeder performance and gastrointestinal health.2. A completely randomised trial was conducted using 300 broiler breeder hens (Ross 308) aged 51 weeks old which were randomly allocated to 1 of 5 dietary treatments with 6 replicates per treatment in a 10 week trial. Treatments included (1) the basal diet a negative control, (2) basal diet supplemented with 0.1 g/kg multi-strain probiotic (MS), (3) basal diet supplemented with 0.1 g/kg single-strain probiotic (SS), (4) basal diet supplemented with 0.1 g/kg of both of probiotics (MS+ SS) and (5) positive control basal diet supplemented with 0.5 g/kg oxytetracycline antibiotic (OX).3. Body weight, egg production, yolk weight, eggshell thickness and weight, Haugh unit, fertility and hatchability were determined. Results showed that dietary treatments had no significant effect on total hen house or total hatching egg production, egg weight, yolk colour index, shell weight, mortality, body weight, fertility, hatchability, oviduct and stroma weight or number of large and small yellow follicles (P > 0.05). None of the jejunum morphological parameters, apparent ileal digestibility of protein and ileal Lactobacillus population were influenced by supplemental probiotics (P > 0.05), although ileum Escherichia coli count was reduced by inclusion of dietary probiotics (P < 0.05).4. It was concluded that although both probiotic treatments reduced coliforms, they did not improve broiler breeder performance or gastrointestinal tract (GIT) function.

Characterisation of the Mycobiota on the Shell Surface of Table Eggs Acquired from Different Egg-Laying Hen Breeding Systems.

Microbial safety is an important factor contributing to the egg quality. During egg acquisition, there is significant risk of contamination of the eggshell surface with microscopic fungi. Mycelial hyphae may grow on the eggshell surface and penetrate into the egg content. However, there is no information on the populations of microscopic fungi on the eggshell surface and, consequently, on possible production of mycotoxins. Therefore, the aim of the study was to identify the species of microscopic fungi present on the eggshell surface acquired from different breeding systems and to measure the number of selected mycotoxins. The qualitative analysis resulted in the identification of 41 isolates on the surface of eggs. There were 7 isolates from the organic production system, 11 from the free-range production system, 14 from the deep litter indoor housing system and 9 from the cage farming production system. The research proved that the diversification in the population of mycobiota on the eggshells depended on the egg-laying hen breeding system. The microscopic fungi isolated from the eggshells included toxigenic and pathogenic species such as Fusarium culmorum and F. equiseti. As the egg storage time increased, fungi, including the pathogenic species, penetrated through the eggshells. In consequence, mycotoxins were identified in the egg whites. Type-A and type-B trichothecenes were found in the eggshell samples containing F. culmorum.

Efficacy of three sealing methods on hatchability of microcracked eggs from broiler breeder hens

Background: Shell fragility of hatching eggs can have negative implications on the economic performance of hatcheries. Objective: To determine the efficacy of sealing eggshell micro cracks with either coloured or uncoloured nail varnish, and molten paraffin on hatchability, embryonic mortality (EM) and hatched chick weight (CW). Methods: Eggs (n= 576) with micro-cracks were assigned among four groups (n=144 each group) for a 21 d incubation period. One group was untreated (CE). In the other groups, the micro cracked area of eggshells was sealed with uncolored nail varnish (NV), colored nail varnish (CV), or molten paraffin wax (MP). A positive control group of un-cracked eggs (UE) was also included (n= 144). Results: The eggshell sealant treatments allowed normal conductance related to egg weight loss after 18 d of incubation (11.45%), and chick weights were normal among treatment groups (44.7 g). Hatchability and embryonic mortality in the early and late incubation periods of the NV group was similar to UE (84.02 vs 86.11% for hatchability, 6.95 vs 10.42% for EM on days 1-10, and 2.08 vs 1.39% for EM on days 18-21 respectively; p>0.05). The CV group had lower hatchability than the NV (77.77 vs 84.02% respectively; p 0.05). Conclusions: Application of uncoloured nail varnish on shell micro-cracks improves egg hatchability. Keywords: Eggshell, embryonic mortality, hatching, incubation, micro fissure repairing, poultry. Resumen Antecedentes: la rotura de la cascara es un problema que afecta a los huevos para incubacion, reduciendo la eficiencia economica de la produccion. Objetivo: determinar la eficacia del sellado de micro grietas de huevos utilizando parafina fundida, esmalte de unas transparente, o esmalte de color sobre la incubabilidad, mortalidad embrionaria (EM) y peso de los pollitos (CW). Metodos: los huevos (n= 576) con micro fisuras fueron asignados a uno de cuatro grupos durante un periodo de incubacion de 21 dias. Un grupo se mantuvo sin tratar (CE), en los otros grupos se sello el area micro-agrietada de la cascara con esmalte incoloro de unas (NV), esmalte de color (CV), o parafina fundida (MP). Tambien se incluyo un grupo de huevos no agrietados (UE, n= 144). Resultados: los tres tratamientos aplicados a la cascara permitieron obtener una perdida de peso normal de los huevos a 18 d (11,45%), asi como un peso normal de los pollitos (44,7 g). El grupo NV presento incubabilidad y EM similares a UE durante el periodo de incubacion (84,02 vs 86,11% incubalidad y 6,95 vs 10,42% EM entre los dias 1-10; y 2,08 vs 1,39% EM entre los dias 18-21 respectivamente; p>0,05). El grupo CV tuvo incubabilidad inferior a la de NV (77,77 vs 84,02% respectivamente; p 0,05). Conclusiones : la aplicacion de esmalte incoloro de unas en las micro-grietas de la cascara mejora la incubabilidad de los huevos. Palabras clave : cascara de huevo, eclosion, incubacion, mortalidad embrionaria, produccion avicola, reparacion de micro fisuras. Resumo Antecedentes: a quebra da casca do ovo e um dos problemas mais importantes durante a incubacao, reduzindo a eficiencia economica da producao. Objetivo: determinar a eficacia da selagem de microfissuras na casca de ovo com verniz de unhas, transparente ou colorido, e parafina fundida na eclosao, mortalidade embrionaria (EM), e peso dos pintos ao nascimento (CW). Metodos: ovos (n= 576) apresentando microfissuras foram divididos em quatro grupos (n= 144) e colocados a incubar por um periodo de 21 dias. Um dos grupos nao foi tratado (CE). Os ovos dos restantes grupos foram selados com verniz de unhas transparente (NV), verniz de unhas colorido (CV) ou parafina fundida (MP). Foi ainda incluido um controlo positivo constituido por ovos sem microfissuras (UE) (n= 144). Resultados: em todos os grupos tratados, observou-se uma perda de peso normal apos 18 dias de incubacao (11,45%) assim como um peso vivo normal dos pintos ao nascimento (44,7 g). Observou-se uma taxa de eclosao e mortalidade embrionaria similar dos periodos iniciais e finais de incubacao entre os grupos NV e UE (84,02 vs 86,11% para eclodibilidade, 6,95 vs 10,42% para EM entre os dias 1-10, e 2,08 vs 1,39% para EM entre os dias 18-21 respectivamente; p>0,05). O grupo CV evidenciou uma taxa de eclosao menor do que a do grupo NV (77,77 vs 84,02% respectivamente; p 0,05). Conclusoes: o uso de verniz de unas transparente e um metodo apropriado para incrementar a eclodibilidade de ovos com microfissuras. Palavras-Chave: casca de ovo, incubacao, mortalidade embrionaria, producao de aves, reparacao de fissuras, taxa de eclosao.

Genetic parameter estimates for juvenile body weight in indigenous Uttara chickens

The aim of the present study was to estimate genetic parameters of juvenile body measurements in indigenous Uttara chickens. Body measurement records at birth of 1907 chicks sired by 25 breeder cocks and 200 breeder hens were used in heritability calculation. Genetic parameters were estimated for Uttara chicken juvenile body weights at hatching, and at 4 weeks, 8 weeks, 12 weeks, 16 weeks and 20 weeks of age. Heritability of all body measurements was estimated by paternal half-sib method. Heritability estimates can be used to improve body measurements of indigenous Uttara hens. The sex dimorphism effects were estimated at 2 weeks of age and were present at later ages. These results indicate that mass selection method based on the individual phenotype of the chickens at different ages can provide genetic improvement in the flock. Thus, early body measurements of the Uttara chickens could be used for prediction of the size of the adult Uttara.

Histomorphometrical changes of oviduct during the long-term exposure of breeder hens to extra thyroxine.

In this research a 100 day long treatment period was considered to unmask the probable adverse effects of long-term induced hyperthyroidism on histomorphometrical attributes of the oviduct in broiler breeder hens. A total of seventy 47-week-old Cobb 500 breeder hens were randomly allotted to two treatment groups (5 replicates of 7 hens each). Thyroxine (T4) was orally administered to the hyperthyroid group (0.3 mg/bird/d) for 100 consecutive days; whereas the control group received drinking water only throughout the trial. At 64 weeks of age, 2 birds per replicate were killed by cervical dislocation and their oviducts were removed. For histomorphometrical observations, segments were taken from five different regions. After tissue preparation and staining with haematoxylin and eosin, histological layers were evaluated using light microscopy. The assessment of histomorphometrical characteristics of oviduct showed the height of mucosal folds in the magnum, thickness of mucosal folds of the magnum and uterus, thickness of tunica muscularis in the magnum and vagina, epithelial thickness of the isthmus and vagina, and uterine tubular glands percentage were decreased in the hyperthyroid birds compared with the control counterparts. The results showed long-term induced hyperthyroidism was associated with a decrease in a number of histomorphometrical traits in different regions of the oviduct. Some studies should be done to clarify to what extent the long-term maternal hyperthyroidism might affect the egg production, fertility rate, duration of fertility, and sperm penetration rate to make a final decision on exploitation of this preventative treatment to diminish the ascites incidence in progeny chicks.

Effect of restricted feed intake in broiler breeder hens on their stress levels and the growth and immunology of their offspring.

The prenatal environment has been shown to have significant effects on the lifelong health of offspring in humans and other species. Such effects have not been studied extensively in avian species but could prove important, especially in the case of severe feed restriction imposed on broiler breeder hens to prevent obesity and reduce rate of lay. Feed restriction can potentially affect not only nutrient supply to the embryo but stress hormone levels within the hen. This study investigated the impact of nutrient restriction of the breeder hen on growth rate and immune responses in the progeny with the objective to measure the impact of feed restriction of broiler breeder hens on growth and immune response of the progeny. Broiler breeder hens were feed restricted from 24 wk of age and maintained at three bodyweights; 3.4, 3.6, and 4.0 kg until 43 wk of age and behavioral and physiological measures of stress recorded. Chicks were hatched from each hen treatment and at day 7 vaccinated for infectious bronchitis virus (IBV) and at 16, 18, and 20 d old given an immune challenge of lipopolysaccharide. Growth and immune responses of these birds were then recorded. Sex ratio was affected by hen bodyweight, with a significantly increased proportion of males hatched from heavy hens. Growth rate from 35 to 42 d of age was reduced in male progeny from low bodyweight hens. Female progeny from heavy hens responded to an immune challenge by reduced live weight and increased heterophil: lymphocyte ratio, suggesting a more robust immune response in these birds than in the progeny from lower bodyweight hens. Overall, progeny from heavy hens had increased antibodies at day 35 to the vaccination of IBV compared with progeny of low bodyweight hens, also suggesting an improved immune response in these birds. Breeder hens restricted to the lowest feed level showed behaviors indicative of increased stress (object pecking) and an increased heterophil: lymphocyte ratio. Feed restriction of broiler breeder hens increased indices of stress in hens and resulted in offspring that have reduced growth rate and immune response in a sex-dependent way.

Utilization of soy hulls, oat hulls, and flax meal fiber in adult broiler breeder hens

A total of 72, 65-week-old broiler breeder hens (Ross 308, BW 4,190 ± 45g) was placed in individual cages to investigate utilization of fiber in soy hulls (SH), oat hulls (OH), and flax meal (FM). Birds were adapted to cages for 10 d prior to allocation (n = 18) to broiler breeder ration (control) or control mixed with either of the 3 fiber sources (wt/wt) added to supply equal amounts of neutral detergent fiber (NDF) ∼21% and TiO2. The daily feed allocation was based on 4% BW. Feed intake (FI) was monitored daily, and grab excreta samples were taken on d 16 and 17. On d 18, all birds were weighed and killed 2h post feeding to measure ceca digesta pH and short chain fatty acids (SCFA). Relative to the control birds, birds receiving fiber lost (P < 0.05) BW due to decreased (P < 0.05) FI. The BW changes were respectively +80, -174, -133, and -585g/bird for control, SH, OH, and FM, and corresponding FI was 1,062, 918, 885, and 590g/bird. Birds fed FM retained higher (P < 0.05) NDF than birds fed either SH or OH. The ceca digesta pH was lower (P < 0.05) in birds receiving added fiber relative to control. However, ceca digesta pH of FM fed birds was lower (P < 0.05) than in birds fed either SH or OH, which were in turn similar (P > 0.05). Birds fed FM had higher (P < 0.05) concentration of butyric acid than birds fed the control diets, while birds fed SH and OH had intermediate butyric acid concentration. Acetic acid and total SCFA concentrations were higher (P < 0.05) in birds fed OH diet than in birds fed control but was similar (P > 0.05) to that in birds fed either SH or FM. In conclusion, short term feeding of fibrous feed ingredients reduced BW linked to reduced FI. Fiber sources exhibited differences in utilization reflective of chemical characteristics.

Effects of maternal dietary canthaxanthin and 25-hydroxycholecalciferol supplementation on antioxidant status and calcium-phosphate metabolism of progeny ducks

Three experiments were conducted to investigate the effects of maternal dietary canthaxanthin (CX) and 25-hydroxycholecalciferol (25-OH-D3) supplementation on antioxidant status and calcium-phosphate metabolism of progeny ducks. Cherry Valley duck breeders (38 wk old) were fed either a control diet or the same diet plus CX (6mg/kg) and 25-OH-D3 (0.069mg/kg) for 32 weeks. Experiments 1, 2, and 3 were conducted with progeny ducks hatched from eggs laid by duck breeder hens at 54, 62, and 70 wk of age, respectively. Progeny ducks from both maternal treatments were fed with the same NRC (1994) vitamin regimen starter (1 to 14 d) and finisher (15 to 35 d) diets in experiments 1 and 2, and fed with the same high vitamin regimen starter (1 to 14 d) and finisher (15 to 35 d) diets in experiments 3. High vitamin regimen had higher levels of all vitamins, except biotin, than the NRC (1994) vitamin regimen. In experiment 1, maternal CX and 25-OH-D3 increased (P < 0.05) shank pigmentation and tibiotarsus ash and tended to decrease (P < 0.1) liver total superoxide dismutase activity (T-SOD) of one-day-old progeny ducks; and increased (P < 0.05) shank pigmentation, decreased (P = 0.05) liver protein carbonyl, and tended to increase (P < 0.1) liver total antioxidant capacity (T-AOC) of 14-day-old progeny ducks. In experiment 2, maternal CX and 25-OH-D3 increased (P < 0.05) shank pigmentation and liver T-AOC and decreased (P < 0.05) liver protein carbonyl of one-day-old progeny ducks, but increased (P < 0.05) the serum phosphate level of 14-day-old progeny ducks. In experiment 3, maternal CX and 25-OH-D3 increased (P < 0.05) shank pigmentation of one-, 14-, and 35-day-old progeny ducks and tended to increase (P < 0.1) liver T-SOD and tibiotarsus ash, but decrease (P < 0.1) liver malondialdehyde of one-day-old progeny ducks. It can be concluded that progeny dietary high vitamin regimen could partially prevent maternal CX-derived progeny shank pigmentation from bleaching. Maternal CX- and 25-OH-D3-derived effects are influenced by the hen's age and progeny's dietary vitamin regimen.

Energy partitioning at low temperatures in broiler breeders

The objective of the present study was to investigate how broiler breeder hens partition dietary metabolisable energy (ME) at low temperatures. Performance of caged broiler breeders fed equal quantities of essential nutrients (other than energy) was measured in six environmental chambers, with the temperature in each chamber being kept constant at 10°C, 12.5°C, 15°C (two chambers), 17.5°C or 20°C for two 6-week periods. Throughout these two trial periods, birds were fed 160 g/day of one of four diets containing 12.9, 11.9, 10.5 or 9.7 MJ apparent ME/kg, so that daily energy allocations ranged from 1552 to 2964 kJ/bird. Irrespective of the environmental temperature to which they were subjected, broiler breeders consumed virtually all of the feed allocated to them each day. Mean rate of lay and egg output in the final 3 weeks of each period of hens on the highest apparent ME feed was unaffected by the decrease in temperature from 19.5°C to 9.9°C, but equally depressed on the three lower energy levels. Both weight gain and egg weight increased marginally, but significantly, as the temperature decreased. As a function of body protein weight (BP, kg), egg output (EO, g/day) and growth (ΔW, g/day), the ME consumed (kJ/day) by broiler breeders over all treatments was partitioned as follows: 2423 (±30.3) BP + 7.04 (±0.41) EO + 13.5 (±1.10) ΔW. An ME intake of 1900 kJ/bird.day would appear to be adequate for broiler breeders over the range of temperatures used in the trial.