Relationships Between Fertility and Some Parameters in Male Broiler Breeders (Body and Testicular Weight,Histology and Immunohistochemistry of Testes,Spermatogenesis and Hormonal Levels)

In a farm of grandparent broiler breeder chickens, we followed the development of 350 roosters from 6 to 55 weeks of age. Data collected and evaluated from these males included body weight, testicular weight, histologic and immunohistochemistry studies of the testes, hormone levels (testosterone, estradiol and corticosterone) and sperm production. The objective was to understand the factors that affect or influence hatch loss that is commonly observed after 45 weeks of age in breeder flocksare often correlated to broiler breeder male chickens. The results of this study showed that in conjunction with the weight of the rooster, the testicle weight increases quickly after the rooster receives light stimulation. At an older age, the study showed that there is a process of testicular shrinkage, and the same effect is seen in sperm production and testosterone levels in broiler breeder roosters. From the histology evaluation, we defined 5 histologic phases that illustrate the evolution of the testicular tissue: perinatal, infantile, puberty, adult and senile. We observed that the adult males with a body weight <3800 g were infertile or had subfertile levels and also had low levels of testosterone and high levels of corticosterone. In contrast, the heaviest males showed correct testicular vitality, high levels of testosterone and low levels of corticosterone. However, the roosters that had acquired this high body weight were also at risk of having less complete copulations because of their physical mass. The loss of uniformity of the males and the appearance of hierarchies within the flock accompany a decline in the percentages of hatches as a consequence of the poor confirmation of the males for copulation or the restriction to the access to the females. Results of this study show that the decrease in fertility from 45 weeks of age has been associated with a decline in testicular weight, sperm production and the testosterone levels in animals with a sub‐par weight. Likewise, decreasing hatch in older flocks may also result from a loss of conformation, and the lack of complete copulations is possible because of animals that are grossly overweight.     

The relationships between dietary crude protein, body weight, and fertility in naturally mated broiler breeder males

1. Naturally mated male broiler breeders were fed to achieve five levels of body weight gain on a high (160 g crude protein (CP)/kg) or low (110 g CP/kg) protein diet. Males were separately fed in 9 of the experimental treatments and fed with the females in the other. 2. There was an optimum body weight for maximum fertility which changed with age. The best fertility was shown by males weighing 3.2 kg at 26 weeks rising to 4.0 kg at 60 weeks of age. 3. The low protein diet was associated with higher fertility, particularly during the latter part of the breeding period (49-60 weeks). 4. Head width reached a plateau after 26 weeks of age and was 1 mm greater in males weighing more than 5 kg compared with males weighing 3 to 4 kg at 60 weeks of age.     

Cottonseed Meal Diets Improve Body Weight Uniformity in Broiler Breeder Pullets

Due to its low nutrient density, cottonseed meal (CSM) may be a potential alternative feed ingredient for soybean meal (SBM) in broiler breeder pullet diets to improve flock BW uniformity. A major concern when utilizing CSM in poultry diets, however, is the presence of gossypol. It was determined in an initial experiment that when broiler breeder hens are fed a diet containing CSM, gossypol accumulates in the liver. When CSM is removed from the diet, however, hepatic gossypol levels dissipate within a few weeks. In a subsequent study, in order to achieve the breeder guideline ideal weight, broiler breeder pullets reared with a diet containing CSM from 2 to 18 wk of age had to be fed a larger amount than birds consuming a standard SBM diet. The CV of bird weight was significantly lower during the rearing period for birds reared with the corn and CSM diet. This difference in uniformity was maintained as the hens entered the breeding period. Egg weight, hatchability, and fertility were equivalent for hens reared with a diet containing CSM and those reared with a standard diet throughout the growing period. The results suggest that broiler breeder pullets reared on a diet containing CSM as the major protein source have improved flock BW uniformity and normal subsequent reproductive performance.     

Early body-weight selection of broiler breeder males in relation to reproductive and growth performance of their offspring

1. The effectiveness of selection of broiler breeder males for body weight at 3 weeks of age on later growth, semen quality and performance of progeny has been tested. 2. Correlation between 3- and 20-week body weights in the breeders was poor but significant. 3. On the basis of 3-week body weight males were divided into heavy birds (mean + 0.5 standard deviation) and all birds. 4. Semen quality was not different between the two groups, but some selection for semen quality was practised within groups. 5. There were no differences in fertility and hatchability of eggs produced from hens artificially inseminated with diluted, stored semen from both groups. 6. There was a small, positive, but non-significant, effect of selection of breeder males on body weight of progeny at 6 weeks of age.     

End-of-Season Carcass and Reproductive Traits in Original and Replacement Male Broiler Breeders

Reproductive efficiency of male broiler breeders declines toward the end of a production cycle. It is common to add young, replacement males (spiking) to a breeder flock to maintain or increase fertility. To date, no study has reported if there are differences in the carcass and reproductive morphology between original and spiked males at the end of the breeding period. In this study, the weight, fleshing traits, footpad condition, and testes size of 327 Hubbard males (237 original and 90 replacement) from a commercial operation were examined. The original birds (63 wk of age) had significantly higher BW, breast weight, girth measurement, keel length, and spur length than the spiked males (48 wk of age). While external indicators of size and fleshing differed betweenreplacement and original roosters, testis weight was not affected by the age of the bird. It was found that average testis weight correlated well with BW in birds in which testicular regression had not taken place but only weakly with spur length. Because original males had a higher BW and were more heavily fleshed than replacement males, their ability to successfully complete matings may have been impeded. Further research is needed to link growth profiles with semen quality, sexual behavioral, and longevity of a male breeder in a commercial flock.     

Application of the Sperm Mobility Assay to Primary Broiler Breeder Stock

A new quantitative trait affecting male fertility was discovered in the 1990s. The term sperm mobility denotes the net movement of a sperm cell population against resistance at body temperature. Even though sperm cells are self-propelled DNA delivery vehicles, their self-propulsive nature is neither uniform among sperm within an ejaculate nor among males within flocks. Such variation is evident when semen quality is evaluated by sperm penetration of an Accudenz solution, hence the term sperm mobility assay. It is noteworthy that populations showing modest variation with respect to semen volume or sperm concentration often show considerable variation with respect to sperm mobility. Likewise, it is noteworthy that broiler breeder fertility is a function of sperm mobility phenotype when hens are inseminated artificially. This article outlines the following: 1) a series of experiments in which the sensitivity of the commercial sperm mobility assay was improved using semen donors from lines of chickens selected for either low or high sperm mobility and 2) the application of the improved technique to pedigree broiler breeders. Male fertility is subject to genetic selection when sperm mobility is the selection criterion. Therefore, sperm mobility may be a useful trait for improving broiler breeder reproductive efficiency.     

Metabolic rate and its relationship with ascites in chicken genotypes

1. Male chickens of 7 genetic lines, consisting of two pure sire and two pure dam populations, a commercial broiler cross and two slow-growing chicken lines (Label Rouge, LR and Mechelse Koekoek, MK) were reared from 1 to 37 d of age. The chickens received a two-phase dietary regime and were subjected to low ambient temperature. 2. The experimental aim was to investigate relationships between susceptibility to ascites and heat production. 3. Body weight gain (BWG), food intake and food conversion ratio (FCR) were determined. Ascites mortality, arterial pressure index (API=right ventricular/total ventricular weight ratio), haematocrit values, proportional lung weight (lung weight/body weight x 100), plasma thyroid hormones (thyroxine, T4 and triiodothyronine, T3) and arterial blood gas pressures (pCO2 and pO2) were determined. The heat production per kg metabolic body weight (H/W0.75) and total heat production (H) were calculated for the period 16 to 33 d using an energy balance study according to the comparative slaughter method. 4. The two breeder sire lines had high BWG and low FCR and high but different incidences of ascites compared with the slow-growing ascites resistant LR and MK lines with notable high FCR. The broiler cross and slower-growing breeder dam lines had a similar and relatively lower incidence of ascites mortality. 5. The fast-growing chickens had low H/W0.75 values compared with slow-growing lines. 6. These fast-growing breeder sires had lower plasma thyroid hormone, reduced proportional lung weights, low arterial pO2 and high arterial pCO2 pressures compared with the slower-growing lines. 7. In conclusion, ascites incidence was associated with lower heat production per metabolic body weight and therefore a lower oxygen requirement per metabolic weight.     

鸡感染REV和ALV-J后血清指标动态变化的研究

研究禽网状内皮组织增生症病毒(REV)、禽J亚群白血病病毒(ALV-J)感染及混合感染引起血清指标动态变化与鸡群体重抑制的关系.3组1日龄哈伯德父母代肉种鸡,分别接种REV、LV-J和REV与ALV-J.定期称量体重,采外周静脉血,通过生化自动分析仪检测鸡血清中总蛋白(TP)、高密度脂蛋白胆固醇(HDL-c)、低密度脂蛋白胆固醇(LDL-c)、甘油三酯(TG)、胆固醇(CHO)的动态变化.结果表明,前7周,血清学指标TP、TG、LDL-c浓度变化与生长抑制的变化呈现相关性,随体重的增加,TP、TG、LDL-c浓度有上升的趋势,HDL-c、CHO浓度变化与体重的变化无相关性.因此,检测7周内的血清TP、TG、LDL-c浓度的动态变化与鸡群体重抑制的关系可作为这两种肿瘤性疾病早期诊断的依据.     

Effect of Testosterone Administration and Spiking on Reproductive Success of Broiler Breeder Flocks

Age negatively affects reproductive success of broiler breeder flocks. One of the main hormones involved in the change of fertility with the age is testosterone (TT). The introduction of young males at later production stages of broiler flocks is known as spiking and is expected to reduce the fertility decline with age. The aim of this study was to determine the effect of injection of different levels of TT and the effect of spiking on reproductive fitness of broiler breeder flocks. Two experiments were conducted on Ross 308 breeder flocks for 10 weeks (41–50 weeks of age). The experiment 1 included a control and three treatments corresponding to three doses of TT (0.1, 0.2 and 0.3 cc), while the experiment 2 included a control and one treatment corresponding to spiking. The lower dose of TT (0.1 cc) and the spiking clearly slowed down the decline in hatchability. Therefore, either the external administration of TT to the males when the natural concentration of TT starts to decline or spiking the breeder flock with young roosters could contribute to improve reproductive success in later stages of the production cycle in broiler breeder flocks.     

种公鸡日粮营养水平及其对繁殖性能影响的研究

用29～36周龄海赛克斯(褐色)蛋用型父母代种公鸡112只、种母鸡1024只,研究了种公鸡日粮营养水平及其对繁殖性能的影响。上述试鸡,种母鸡饲用同一蛋鸡料,种公鸡则分别给饲下列4种日粮:1.高CP(17.5％),高AA(0.86％L_(Ys),0.63％SAA),高Ca(3.7％)日粮;2.CP(12.5％),低AA(0.55％L_(YS),0.45％SAA),高Ca(3.7％)日粮; 3.低CP(12.5％), 低AA(0.55％ L_(Ys), 0.45％SAA), 低Ca(1.0％)日粮;4,同3,仅更换维生素-微量元素综合预混料。结果:1.采用低CP、低AA、高Ca或低CP、低AA、低Ca日粮时,种公鸡的精液品质、种蛋受精率、孵化率等均无异于用高CP、高AA、高Ca日粮者(P>0.05);2.采用种公鸡专用维生素-微量元素综合预流料,入孵蛋孵化率提高3.35％,日饲用低CP、低AA、低Ca日粮的种公鸡体增重(29～36周龄)大于用高CP、高AA、高Ca日粮者(P<0.05),其36周龄体重较接近于品种标准。     

Can testosterone and corticosterone predict the rate of display of male sexual behaviour,development of secondary sexual characters and fertility potential in primary broiler breeders?

1. Genetic selection for growth to enhance production may be associated with stress and with modified physiological and behavioural phenotypes which depress male primary broiler breeder fertility. 2. We hypothesised that male serum testosterone (T) and corticosterone (C) concentrations might correlate with fertility, sexual behaviour, and testicular, comb and wattle size. 3. Cockerels from two genetic strains (A and B) of primary broiler breeder were penned individually with an average of 10 females across 5 age periods (30 to 51 weeks) to evaluate male fertility, behaviour, serum T and C, and comb, wattle and testicular dimensions. 4. Strain A males had higher T at age periods 2, 4 and 5 than Strain B. Both strains had basal concentrations of C, apart from an elevated concentration for Strain B in period 5. 5. Strain B had a weak but significant, positive correlation between sexual behaviour and T and C, while Strain A males with higher C had larger combs and wattles. 6. Neither T nor C correlated with fertility. We conclude that evaluation of these endocrine factors (quantifiable measurements with the potential to correlate with fertility) alone seems insufficient to predict male fertility potential in these strains of primary broiler breeder.     

爱拔益加肉鸡父母代后备期的生长性能分析

肉种鸡的后备期生长发育状况对其产蛋期有很大的影响,后备期的生长性能是否达标,是保证产蛋数量和质量的先决条件,也是提高种鸡场经济效益的关键环节。汇总并分析了实际生产中爱拔益加肉鸡父母代种鸡场的第一手资料,结合理想状态下的生产性能标准,通过直观的数据表和曲线图展示了后备期生长性能以周为单位的波动情况,进而对如何缩小实际值与理论值的差距,如何提升后备期生长性能,以及采用何种措施加强饲养管理工作做了深入分析,以期提高广大养殖户对肉种鸡后备期生产管理的重视程度,切实做好产蛋之前的准备工作,以获得更大的经济效益,为市场供应更多更优质的产品做出贡献。     

Effects of ad libitum feeding on performance of different strains of broiler breeders

(1) Tolerance to ad libitum feeding was compared in three genotypes of broiler breeder hens: a standard broiler breeder fed ad libitum (SA) or restricted (SR), a slow growing 'label' broiler breeder (L) and an experimental dwarf heavy broiler breeder (E). Two similar experiments were conducted in two distinct research centres. (2) Feed intake and body weight were measured every 3 weeks from hatch to 40 to 49 weeks of age. Egg production and egg abnormalities were recorded. The number of yellow follicles in ovaries was counted at the age of 32 weeks. (3) Body weight was stabilised at 2.2, 3.7 and 5.4 kg after 24 weeks of age in L, E and SA hens, respectively. Growth of the SR hens was similar to that of L up to 20 weeks and stabilised at a similar level to that of E hens after 30 weeks of age. (4) Sexual maturity was delayed by 6 weeks in restricted breeders compared to ad libitum fed hens that started to lay at 20 weeks. SA hens had low egg production and a high proportion of defective eggs, which was largely compensated for by feed restriction. However, productivity of SR hens remained lower than that of L breeders. (5) Compared to the low viability and reproductive fitness observed with SA hens, the E dwarf broiler breeder tolerated ad libitum feeding and had better egg production, fewer egg abnormalities and yellow follicles per ovary and a higher egg production. However, laying rate was still lower than that of the SR and L groups. Energy conversion (kJ/g egg) from 32 to 40 weeks of age was much higher in the SA group than in the other three groups. 6. The feasibility of feeding a dwarf broiler breeder ad libitum calls for further research on implications of specific IGF and GH-receptor expression at the level of the ovary in dw chickens.     

Effect of feeding guanidinoacetic acid and L‐arginine on the fertility rate and sperm penetration in the perivitelline layer of aged broiler breeder hens

Two experiments were conducted to evaluate the effects of feeding guanidinoacetic acid (GAA) and L‐arginine (ARG) on fertility and sperm penetration (SP) rate of broiler breeder hens. In the first experiment, a total of 200 broiler breeder hens (Ross 308) aged 53 week were randomly allotted to four dietary treatments (0, 0.6, 1.2 and 1.8 g GAA/kg diet) with five replicates of 10 birds each. In the second experiment, 320 broiler breeder hens (Ross 308) were used from 53 to 62 weeks of age in a 2 × 4 factorial arrangement (0 or 1.2 g GAA/kg diet along with 0, 3, 6 or 9 g ARG/kg diet). The hens received a diet containing 2800 kcal ME/kg and 14% CP. Sixteen sexually mature Ross 308 breeder roosters (34 weeks old) were used to artificially inseminate the hens. Fertility of the hens was determined in 61 and 62 weeks of age. The sperm penetration holes in the inner perivitelline layer (IPL) overlying the germinal disc were enumerated on days 3 and 7 following each insemination. Adding GAA to the breeder diet increased the number of SPs in the IPL and fertility in both experiments (p < 0.01). The interactive effect of ARG and GAA on the SP and fertility was significant. Supplementary ARG increased the SP rate in the IPL (p < 0.01). In conclusion, dietary supplementation of GAA and ARG might be potentially used to improve the fertility of broiler breeder hens at the later phase of the egg production period.     

Selection for early response to photostimulation in broiler breeders

1. To determine if selection for early response to photostimulation could be successful, 150 male broiler breeders were photostimulated at 8 weeks of age. The first 20 to produce a semen sample and have a reddened comb with an area > 10 cm2 were selected as responders (R) and 20 birds that did not show these signs of sexual development were chosen as non-responders (NR). Once sexually mature, 8 birds from each group that consistently produced a semen sample were mated with both egg-type hybrids and broiler breeder females to observe the response to 8-week photostimulation in the as-hatched offspring. 2. The AFE of the F1 females with NR or R paternity and egg-type hybrid layer maternity (F1L) were similar, but AFE was advanced in birds from R relative to NR paternity when they had broiler breeder maternity (F1B). 3. Date following a normal distribution of AFE were extracted from the overall data set. This group included offspring from both NR and R paternity, but AFE in F1L and F1B females with R paternity was advanced compared to those with NR paternity. 4. Mean testis weights, or age at most rapid testis growth predicted using parameters from Tyler and Gous (2009), of F1 males were not significantly different in birds with NR or R paternity. A strong correlation was found between predicted age at most rapid growth and AFE of full sibs and so it is likely that an advance in AFE in female offspring would also result in an advance in age of testis development of males. 5. There was no significant difference in 21-d body weight of F1B females of NR or R paternity, but the 21-d body weights of F1L females were higher from R than from NR sires, suggesting that although fertility and meat-type traits are often negatively correlated, there was no adverse effect of selection for responsiveness to early photostimulation and broiler growth rates to 21 d. 6. These findings showed that the response to early stimulation is heritable, and should be useful to the broiler breeder industry, where a reduction in photorefractoriness would improve egg production and fertility.     

Potential of chemical regulation of food intake and body weight of broiler breeder chicks

1. Two experiments were performed to evaluate the potential of phenylpropanolamine hydrochloride and monensin sodium as appetite- and weight-control agents for Indian River broiler breeder chicks. 2. In experiment 1, a total of 300 day-old sexed broiler breeder chicks were individually weighed and placed in battery cages. They were randomly assigned to 5 dietary treatments, namely 0, 50, 100, 200 and 400 mg/kg of phenylpropanolamine hydrochloride added to a maize-soyabean meal basal diet. 3. In experiment 2, a total of 400 day-old sexed broiler breeder chicks were randomly assigned to 10 dietary treatments which were a combination of two concentrations of dietary crude protein (200 and 150 g/kg) and 5 different concentrations of added drugs in the diet, namely 0, 500 and 800 mg/kg of phenylpropanolamine hydrochloride and 200 and 300 mg/kg of monensin sodium. 4. Food consumption and body weight gain were significantly reduced by feeding diets containing the drugs but mortality was not significantly affected. Birds showed evidence of increased tolerance, with age, to phenylpropanolamine but not to monensin. 5. Monensin sodium, at high inclusion rates, was found to be a more potent and effective appetite- and growth-depressing agent for broiler breeder chicks than phenylpropanolamine and may have application in broiler breeder production using an ad libitum feeding programme.     

Modelling energy utilisation in broiler breeder hens

1. The objective of this study was to determine a metabolisable energy (ME) requirement model for broiler breeder hens. The influence of temperature on ME requirements for maintenance was determined in experiments conducted in three environmental rooms with temperatures kept constant at 13, 21 and 30 degrees C using a comparative slaughter technique. The energy requirements for weight gain were determined based upon body energy content and efficiency of energy utilisation for weight gain. The energy requirements for egg production were determined on the basis of egg energy content and efficiency of energy deposition in the eggs. 2. The following model was developed using these results: ME = kgW0.75(806.53-26.45T + 0.50T2) + 31.90G + 10.04EM, where kgW0.75 is body weight (kg) raised to the power 0.75, T is temperature ( degrees C), G is weight gain (g) and EM is egg mass (g). 3. A feeding trial was conducted using 400 Hubbard Hi-Yield broiler breeder hens and 40 Peterson males from 31 to 46 weeks of age in order to compare use of the model with a recommended feeding programme for this strain of bird. The application of the model in breeder hens provided good productive and reproductive performance and better results in feed and energy conversion than in hens fed according to strain recommendation. In conclusion, the model evaluated predicted an ME intake which matched breeder hens' requirements.     

Salmonella contamination of hatching and table eggs: a comparison.

This study determined and compared Salmonella contamination rates of pools of surplus, early and culled hatching eggs from layer and broiler breeder flocks, and of pools of early and regular table eggs from layer flocks. Each pool contained 6 eggs. Five methods were used for the isolation of Salmonella. Nine of 126 pools of culled layer hatching eggs, 2 of 126 pools of surplus layer hatching eggs, and one of 126 pools of early layer hatching eggs were contaminated with Salmonella. All 126 pools of broiler breeder surplus, and early and culled hatching eggs tested negative for Salmonella. All 168 pools of regular table eggs tested negative for Salmonella, whilst one of 84 pools of early table eggs contained Salmonella agona. The pools of culled layer hatching eggs and surplus layer hatching eggs that contained S. typhimurium were derived from the same breeder operation. Similarly, the pools of culled and early layer hatching eggs that contained S. heidelberg were derived from one breeder operation. Pools of culled hatching eggs were more frequently contaminated with Salmonella than other hatching or table eggs. Pools containing eggs that were both cracked and dirty were more frequently contaminated with Salmonella than all other pools of eggs. The overall Salmonella contamination rate of the table eggs was 0.07 to 0.4%. Critical control points (macroscopic classification of the eggs as cracked and dirty) were validated microbiologically.     

Use of low protein grower diets to delay sexual maturity of broiler breeding males 1

Two experiments were conducted to determine the effects of delaying sexual maturity of broiler breeder males on subsequent reproductive performance. Four dietary protein levels (16.0, 12.4, 8.9 and 5.1 per cent) were fed during the growing period. Thereafter, all males were fed a diet containing 17.0 per cent protein.

Sexual maturity was delayed 4 and 8 weeks, respectively, by feeding the 8.9 and 5.1 per cent protein diets, but was not affected by feeding the 12.4 per cent protein diet. Viability was superior for males receiving the diets containing 8.9 or 5.1 per cent protein. The low protein diets had no adverse effects on semen production, fertility or hatchability following recovery from the protein restriction.     

Stability of dietary ascorbic acid and the effect of supplementation on reproductive performance of broiler breeder chickens

1. The purpose of the study was to determine the stability of dietary ascorbic acid and the reproductive responses of broiler breeder chickens to supplemental 75 mg ascorbic acid/kg diet. 2. Six breeder flocks of 13,000 birds each were studied. Egg production, eggshell porosity, fertility, hatchability and plasma ascorbic acid were measured. 3. Storage of the diets under dry heat resulted in a linear decrease in ascorbic acid content and the rate of decline was 5-fold higher in the supplemented diet. 4. Differences were not detected between treatments in egg production, egg weight, eggshell porosity, fertility, hatchability or plasma ascorbic acid. 5. The results did not provide evidence of a beneficial reproductive response to the inclusion of ascorbic acid in commercial broiler breeder diets.