Dual-purpose Hens Research Articles

Impact of Omega-3/omega-6 fatty acid ratios and photoperiod on productivity, reproductive performance and immune response of dual-purpose hens

Impact of Omega-3/omega-6 fatty acid ratios and photoperiod on productivity, reproductive performance and immune response of dual-purpose hens

Changes in the Oxidative Status of Dual-Purpose Hens Rearing in the Free-Range System during Cold, Thermoneutral and Hot Period.

Simple SummaryNowadays, most consumers prefer table eggs from free-range laying hens. At the same time, relatively few studies exist on the possible effects of free-range rearing on the oxidative status of fowls and their egg production. This trial studied the influence of environmental conditions (cold, thermoneutral and hot period) on the oxidative status of different genotypes of free-range laying hens and the effect of oxidative stress (OS) on their egg production. The factor “temperature period”, compared to “year” and “genotype”, had the most significant influence on all biochemical parameters determining OS. The chicken genotypes showed differences in their susceptibility to OS, and this had an effect on egg production. The OS is genotypically specific and can play a significant role in determining welfare and egg production in free-range systems.This study aimed to assess the changes in the oxidative status of six genotypes of free-range laying hens during cold, thermoneutral, and hot periods by measuring the levels of lipid peroxidation (LPO), total glutathione (tGSH), and the activity of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in erythrocyte suspension, in relation with their egg production. Two identical experiments were conducted in two consecutive years. Thermal stress adversely affected the oxidative status of hens. The induced OS is expressed by an increase in LPO and the activities of antioxidant enzymes SOD and GPx during cold and hot periods and a decrease in CAT and tGSH during the cold period in both years. The factor “temperature period”, compared to “year” and “genotype”, had the most significant influence on all biochemical parameters (p < 0.001). Significant phenotypic correlations (p < 0.05) were detected among studied biochemical parameters, except between SOD and tGSH. The chicken genotypes showed differences in their susceptibility to OS and this had an effect on egg production—from 37.87% to 74.93%. The OS is genotypically specific and can play a significant role in determining welfare and egg production in free-range systems.

Productive performance, perching behavior, keel bone and other health aspects in dual-purpose compared to conventional laying hens

Several alternatives to avoid killing male day-old chicks are available. One of these alternatives is to keep dual-purpose chicken strains. The aim of this study was to compare dual-purpose hens (Lohmann Dual, LD) with conventional laying hens (Lohmann Tradition, LT) in terms of performance, animal welfare parameters such as keel bone state and foot pad dermatitis, and perching behavior. We expected a generally equal or even better performance of the dual-purpose hens except for laying performance. Four hundred female day-old chicks were housed in 6 pens (3 pens per strain) and reared until 54 wk of age. Each pen offered a littered area, elevated slatted manure pit, elevated wooden frame with perches or grids and nest boxes on the manure pit. The wooden frame was alternately equipped with perches or grids. The elevated manure pit as well as the elevated structure was accessible via ramp. Productive performance parameters like mortality, total number of eggs and body weight were assessed periodically. In week 49, 132 hens (66 hens per strain) were randomly selected for radiography of the keel bone and assessment of plumage and foot pad state. Perching behavior was analyzed via scan sampling during rearing and laying period, respectively. Statistical analyzes were done with Linear Mixed Effect Model and General Linear Mixed Model. LD had a higher radiographic density than LT hens (P = 0.0016), other keel bone parameters (fracture score, P = 0.36; deformation, P = 0.83) showed no differences. The vast majority of fractures occurring in both strains were located in the caudal part of the keel bone. During the laying period, usage of elevated structures was higher with grids compared to perches (P < 0.001) and in LD compared to LT (P = 0.01). Some animal welfare problems were less frequent in LD compared to LT hens while other problems did not differ between the 2 strains or were even more frequent in LD hens. Grids may be more suitable as resting area than perches and may possibly help to decrease the prevalence of keel bone damage.

Carcass Characteristics, Digestive System Traits of Spent Broiler Breeder and Dual-Purpose Hens.

Simple SummaryThe success achieved in the breeding of laying hens and broilers resulted in modern breeding systems. Obtaining meat from laying hens is not a good alternative to intensive broiler production. However, it can be profitable to use this type of production on organic or backyard farms. Dual-purpose hens can be an economical alternative in some production conditions. The aim of the study was to determine the differences between the features of carcasses and the digestive systems of dual-purpose hens and broiler breeders. The compared dual-purpose hens differed significantly (p < 0.05) from broiler breeders in terms of carcass weight and dimensions. Multipurpose hens had significantly lower (p < 0.05) percentages of breast muscles, leg muscles, skin with subcutaneous fat, wings, and carcass remainders. On the other hand, broiler breeders were characterized by significantly greater (p > 0.05) total intestinal length, duodenum, jejunum, ileum, and terminal intestine. Significant differences were noted in terms of the diameter of individual intestinal segments, with the exception of the iliac and cecum intestines. Broiler breeder hens also had a greater mass of internal organs compared to the dual-purpose layer hens.Raising dual-purpose hens for meat is believed to bring more economic benefits to farmers selling products directly to consumers. The aim of the study was to determine the differences between the carcass features and the digestive system of multipurpose hens and spent broiler breeders. In the experiment, 20 carcasses of 70-week-old Rosa 1 dual-purpose hens and 20 carcasses of 62-week-old Ross 308 broiler breeders were used. Measurements of the length of various sections of the intestine and the diameter of individual intestinal segments were made. During the gutting, proventriculus, gizzard, liver, heart, and spleen were separated and then weighed. Dual-purpose hens differed significantly (p < 0.05) from broiler breeders in weight and carcass dimensions. Multipurpose hens were characterized by significantly lower (p < 0.05) percentages of breast muscles, leg muscles, skin with subcutaneous fat, wings, and carcass remainders. Broiler breeders were characterized by significantly longer (p > 0.05) total intestinal length, duodenum, jejunum, ileum, and terminal intestine. Significant differences were confirmed in terms of the diameter of some segments of the intestine. Broiler breeder hens also had a greater mass of internal organs compared to the dual-purpose layer hens.

Impact of Nematode Infections on Non-specific and Vaccine-Induced Humoral Immunity in Dual-Purpose or Layer-Type Chicken Genotypes.

Nematode infections may induce immune-modulatory effects and influence host-immune responses to other pathogens. The aim of the study was to investigate whether a mixed nematode-infection influences non-specific and vaccine-induced humoral immunity against Newcastle Disease Virus (NDV), Infectious Bronchitis Virus (IBV), and Avian Metapneumovirus (AMPV) in already vaccinated hens of a dual-purpose (Lohmann Dual, LD) or a layer genotype (Lohmann Brown Plus; LB). Until 17 weeks-of-age, LD (n = 70) and LB (n = 109) hens were vaccinated against major bacterial and viral diseases and coccidiosis. At 24 weeks-of-age, the hens received either a placebo or an oral inoculation of 1,000 infectious eggs of A. galli and H. gallinarum. Plasma total immunoglobulin (Ig) isotypes (IgY, IgM, IgA) levels and vaccine-induced antibody titers against NDV, IBV, and AMPV were determined from 2 to 18 weeks post-infection (wpi). Infections had no suppressing effect on total Ig isotypes IgY, IgM, and IgA as well as on vaccine-induced antibody titers against NDV, IBV, and AMPV (P > 0.05). Overall, LB hens had higher levels of IgY, IgM, and IgA than those of LD hens (P < 0.05). There were no differences between IBV titers of the two genotypes (P > 0.05). Independent of infection status of the hens, NDV titers were higher in LB hens than in LD hens at wpi 2 (P < 0.05), but not in following weeks (P > 0.05). Uninfected LD hens had lower AMPV titers than their infected counterparts at 6 and 14 wpi (P < 0.05). Regardless of nematode infection, LD hens revealed a higher risk of responding weak to vaccination against NDV (odds ratio = 5.45; P = 0.021) and AMPV (odds ratio = 13.99, P < 0.001) than did LB hens (P > 0.05). We conclude that nematode infections have no adverse effects on non-specific and vaccine-induced humoral immunity in either genotype. LB hens have higher levels of total immunoglobulin isotypes than LD hens. Except for IBV, vaccine-induced humoral immune responses show a dependency on genotype. Dual-purpose hens show lower responsiveness to vaccinations against NDV and AMPV, possibly due to factors associated with increased body fat reserves in this genotype.

Pecking Behavior in Conventional Layer Hybrids and Dual-Purpose Hens Throughout the Laying Period.

To avoid the killing of surplus male layer chickens, dual-purpose hybrids are suggested as an alternative approach. These strains may offer additional advantages compared to conventional laying hens, for instance, a lower tendency to develop injurious pecking behavior. The aim of this study was to assess the behavior, with focus on pecking behavior, of conventional layers (Lohmann Brown plus, LB+) and dual-purpose hens (Lohmann Dual, LD). About 1,845 hens per strain with intact beaks were housed in four stable compartments in aviary systems. Video-based scan sampling of general behaviors and continuous observations of pecking behavior were carried out between 25 and 69 weeks of life. With the exception of “dustbathing” and “scratching,” hybrid × time during the laying period affected all of the observed general behaviors [F(2, 89) = 3.92–10.81, P < 0.001–0.05]. With increasing age, the LB+ hens performed more general pecking, more locomotion and less comfort and sitting behavior. General pecking and comfort behavior did not change over time in the LD hens, whereas inactive behaviors increased with age. During continuous observations, a significant hybrid x period interaction was found for all forms of pecking behavior [F(2, 89) = 4.55–14.80, P < 0.001–0.05]. The LB+ hens showed particularly more severe feather pecking (SFP), which increased with age. In contrast, SFP remained exceptionally low in the LD hens throughout production. Therefore, dual-purpose hybrids should be considered as an alternative to both avoid the killing of surplus male chickens and the development of SFP in laying hen production.

Are dual-purpose hens less fearful than conventional layer hybrids?

BackgroundExcessive fear in farm animals can lead to chronic stress and thus impair animal welfare. In laying hens, fear responses in several behavioural tests have also been associated with the...

Effect of a “diluted” diet containing 10% lignocellulose on the gastrointestinal tract, intestinal microbiota, and excreta characteristics of dual purpose laying hens

Low performing dual purpose hens have different nutritional requirements compared to conventional hybrid hens. Lignocellulose is a low fermentable polymer, acting as a diet diluent and may influence physiological and digestive processes. This study investigated the effect of a 10% dietary lignocellulose dilution on the development of gastrointestinal organs, intestinal morphology, intestinal microbiota, and excreta characteristics of dual purpose hens. One-day-old female Lohmann Dual chicks were allocated to 12 pens and fed two different diets: A standard control diet (CON) and a treatment diet (LC), based on CON but diluted with 10% lignocellulose (ARBOCEL®). At 52 wk of age, gastrointestinal organs were extracted and weights determined. Colorectal tissue samples were chemically fixed and stained for histomorphological examinations. Cecal digesta samples were analyzed for bacterial metabolites and composition using gas chromatography, HPLC, photometry, and PCR. Excreta dry matter and viscosity was consistently assessed during the trial. LC-fed hens showed increased weights of the gizzard (P = 0.003), small (P < 0.001), and large intestine (P = 0.048) compared to hens fed CON. LC-fed hens had a larger colorectal villus area (P = 0.049), a higher mucosal enlargement factor of villi (P = 0.016) and crypts (P = 0.030) than CON-fed hens. The concentration of short-chain fatty acids (SCFAs) (P = 0.017) and ammonia (P = 0.013) was higher in CON-fed hens compared to LC-fed hens. Bacterial composition and activity was generally not affected by feeding the different diets. LC-fed hens had a higher excreta dry matter content than hens fed CON at 10 (P < 0.001), 17 (P < 0.001), and 22 (P = 0.002) wk of age. Correlation analyses revealed a negative relationship between the concentration of SCFAs in the cecum and the colorectal villus surface area (P < 0.01). In conclusion, the feeding of high levels of lignocellulose increased gastrointestinal organ weights and colorectal surface area in dual purpose laying hens. A higher intestinal surface area in combination with lower concentrations of SCFAs might indicate a compensatory reaction of hens fed LC enhancing the absorption of bacterial metabolites by increasing the intestinal mucosal surface.

The Dual-Purpose Hen as a Chance: Avoiding Injurious Pecking in Modern Laying Hen Husbandry.

Simple SummaryDual purpose chickens are one solution to the killing of male day-old chickens from the layer strains. However, modern laying hen husbandry faces further challenges, for instance, the frequent occurrence of injurious pecking. This behavior is seen as a sign of stress in the offending birds, it causes pain and damage in the victims, and thus impairs the health and welfare of the whole flock. In this study, the behavior of conventional laying hens and dual-purpose hens was evaluated comparatively by assessing the status of their feathers and skin over time. All hens were housed and managed under semi-commercial conditions. Severe feather loss and skin lesions due to injurious pecking only occurred in the conventional layer flocks. Therefore, keeping dual-purpose hens may also be an alternative approach to overcome damaging behaviors in laying hen husbandry.Dual-purpose strains, with hens housed for egg laying and roosters kept for meat production are one alternative to the killing of male day-old chickens. However, dual-purpose hens seem to have additional advantages compared to conventional layers, for instance, a lower tendency to develop behavioral disorders, such as feather pecking and cannibalism. In the present study, three batches of about 1850 conventional layers (Lohmann Brown plus, LB+) and 1850 dual-purpose hens (Lohmann Dual, LD) each, all of them with untrimmed beaks, were observed during production (20–71 (56) weeks of life) in a semi-commercial aviary system. The aim was to investigate whether the hybrid and batch affected the occurrence of injurious pecking, and to identify a detailed time course of the damage caused by this behavior. Therefore, the hens’ plumage and skin condition were assessed as an indicator by means of a visual scoring method. The LB+ hens had higher production performances and higher mortality rates compared to the LD hens. Plumage loss in the LB+ flocks started at 23 to 25 weeks of age, and deteriorated continuously. The LD hens showed only moderate feather loss on the head/neck region, which started at 34 to 41 weeks and remained almost constant until the end of the observations. Compared to feather loss, injuries occurred in the LB+ hens with a delay of several weeks, with a maximum of 8% to 12% of hens affected. In contrast, skin injuries were observed only sporadically in single LD hens. In all batches, hybrid had an effect on the occurrence of feather loss (p < 0.05). Within the LB+ strain, the proportions of hens affected by plumage loss and injuries differed among batches (p < 0.05), whereas this was not the case in the LD flocks. Thus, severe feather pecking and cannibalism seemed to occur in the conventional layer hybrids but not in the dual-purpose hens, though both genetic strains were raised and managed under the same semi-commercial conditions. Therefore, keeping dual-purpose hens should also be considered as an alternative approach to avoid injurious pecking in laying hen husbandry.

Linear Space Requirements and Perch Use of Conventional Layer Hybrids and Dual-Purpose Hens in an Aviary System.

Roosting on elevated perches is a behavioral priority in laying hens, which is well-investigated in both experimental and commercial settings. However, little is known about perching behavior and perch requirements of alternative hybrids, such as dual-purpose hens. The aim of the present study was to gain basic knowledge on linear space requirements and perching patterns of dual-purpose hens (Lohmann Dual, LD) by comparing them to a conventional layer line (Lohmann Brown plus, LB+). About 3,700 hens per genetic strain were housed in two consecutive batches in four compartments of an aviary system with metal perches at different heights above a grid tier. As an indicator for required perching space, the body widths of a sample of individual hens was determined by image analyses. In addition, the use of five differently located perches and one cross-brace (structural element of the aviary system) was assessed by photo-based observations during the light and the dark phase. The LD hens measured an average body width of 15.95 ± 0.08 cm, and thus occupied about 7% more linear space than the LB+ hens (14.77 ± 0.08 cm body width; P < 0.05). Overall perch use was higher during the dark compared to the light phase, both in the LB+ (3.89 ± 0.08 vs. 0.79 ± 0.03 hens/m, P < 0.05) and the LD hens (2.88 ± 0.06 vs. 0.86 ± 0.03 hens/m, P < 0.05). With a maximum of 8.17 hens/m, the LB+ hens preferred to roost on the highest perches available at night. In contrast, the LD hens also rested on the lowest perches, and showed a more even use of all perches provided. During the day, the LD hens seemed to need lower perches for easy access to the feeders, whereas more LB+ hens used the higher perches, presumably to avoid threatening conspecifics. The present results show that preferences for certain perch locations differed between conventional layers and dual-purpose hens, whereas diurnal patterns of perch use were similar in both hybrids. Therefore, perches should be designed and located in an aviary system to meet the specific preferences and behavioral needs of the hybrid housed.

Evaluation of Loss in Vigour of the Dual Purpose French Guinea Fowl and Their Mixed Genetic Grade in Katsina, Nigeria

The effect of genetic grade (strain) on body weight and body linear measurements of the pure grade dual purpose French guinea fowl strain (116 birds) and their mixed genetic grade (32 birds) was determined using a linear mathematical model. Birds were raised under intensive system in Katsina state. Loss in vigour of the pure grade dual purpose French guinea fowl was calculated by difference. There was a significant (P < 0.05) effect of strain (genetic grade) on body weight and body linear measurements. The pure grade dual purpose French guinea fowl cocks and hens had significantly higher body weight and most body linear measurements than counterpart dual purpose mixed genetic grade guinea fowl cocks and hens. The pure grade dual purpose French guinea fowl cocks and hens had lower coefficients of variation (7.76 and 9.60 %) than the dual purpose guinea fowl cocks and hen mixed genetic grades (13.11 and 13.54 %). The dual purpose mixed genetic grade guinea fowl cocks and hens had longer helmet length than counterpart pure grade dual purpose French guinea cocks and hens. Strain (genetic grade) had no effect on tail length of guinea hens. There were high loss of vigour (56.25 and 57.69 %) of helmet thickness followed by (28.82 and 37.38 %) for body weight of the dual purpose French guinea fowl cocks and hens. Body length (3.76 and 0.56 %) and thigh length (4.22 and 1.85 %) respectively for guinea fowl cocks and hens, were the morphometric traits that had the lowest reduction in vigour among all quantitative traits evaluated. The dual purpose French guinea fowl and their mixed genetic grade had higher body weight than counterpart local guinea fowl strains. Introduction of the dual purpose French guinea fowl into the tropics can aid the diversification of rural poultry production.

The Effect of Slaughter Age and the Diet in the Final Growth Phase of Poulards on Productivity and Meat Quality

Abstract The aim of the studies was to evaluate the effect of the diet in the final growth phase and slaughter age of poulards on productivity, dressing percentage, carcass colour and physicochemical properties of meat. The studies were conducted on 78 hybrids obtained by crossing Ross 308 broiler roosters with Rhode Island Red (R-11) dual-purpose laying hens (♂Ross 308 × ♀R-11). Birds were assigned to 3 groups: control group (K) fed starter, grower and finisher diets without addition of dairy products, experimental group S offered a finisher diet supplemented with 4% whey, and experimental group M receiving 4% milk powder supplement in the final growth phase. Spaying procedure was carried out at 8 weeks of age. Poulards were slaughtered at 18 and 20 weeks of age. The studies showed that by using hybrids of dual-purpose hens with broiler roosters for production of poulards, rearing period could be shortened to 18 weeks, and the obtained meat had comparable or even better quality traits compared with poulards slaughtered at 20 weeks of age. Supplementation of poulard diet with 4% whey or milk powder in the final growth phase had a beneficial effect mostly on improvement of sensory properties of meat. There were not many significant differences in meat quality between poulards fed the diet supplemented with milk and whey but instead there were differences between these groups and the control group fed the diet without these additives.

Pecking and piling: The behaviour of conventional layer hybrids and dual-purpose hens in the nest

Oviposition in an appropriate nest is a behavioural priority in laying hens, and layer strains are known to differ in their patterns of nest use. However, besides oviposition, laying hens often show undesired behaviours such as aggression or gregarious nesting in colony nest boxes. The aim of the present study was to obtain basic information on the patterns of nest use and the behaviour in the nest of dual-purpose hens (Lohmann Dual, LD) by comparing them to a conventional layer strain (Lohmann Brown plus, LB+). In addition, the effect of nest location was tested for each hybrid. About 1850 untrimmed hens per genetic strain were housed in four compartments of an aviary system with colony nest boxes on the top tier. Video-based data were recorded in the first (N1) and the sixth nest (N2) in a row of nest boxes in each compartment at three times during the laying period to assess the number of hens per nest, the duration of nest visits of focal animals, and the behaviour of the hens in the nest. In general, a larger number of LD (0.87 ± 0.09–10.63 ± 0.30) than LB+ hens (0.21 ± 0.04–4.90 ± 0.24) was observed per nest box. In both hybrids, more hens were found in N1 compared to N2 (P < 0.05). Except for 43rd–48th weeks of life, the durations of nest visits did not differ between LB+ (09:51 ± 00:41–18:25 ± 00:48 mm:ss) and LD hens (07:14 ± 00:32–17:14 ± 00:32 mm:ss). However, both hybrids spent more time in N2 compared to N1 (P < 0.05). Hybrid effects (P < 0.05) were found for nearly all of the observed behaviours. In particular, LB+ hens performed more total pecking behaviour, whereas LD hens showed more piling in the nest. In the LB+ hens, nest location affected only few of the behaviours. In contrast, nest location effects were found for most of the behaviours observed in the LD hens. Particularly piling occurred to a larger extent in N1. The present results indicate that the patterns of nest use and the behaviour in the nest differed between conventional layers and dual-purpose hens. Within genetic strain, dual-purpose hens seemed to be more affected by nest location than conventional layers.

Impact of an energy- and nutrient-reduced diet containing 10% lignocellulose on animal performance, body composition and egg quality of dual purpose laying hens

ABSTRACTIn response to ethical concerns regarding the killing of day-old male chicks of layer breeds, the use of dual purpose chickens is increasingly discussed in public while data on nutritional requirements of dual purpose laying hens are not available. The present study examined the impact of an energy- and nutrient-reduced diet containing lignocellulose on performance, body composition and egg quality of dual purpose hens. Female Lohmann Dual chicks were allocated to 12 pens and fed two different diets for 52 weeks: a control (CON) and a treatment diet (LC), based on CON but diluted with 10% lignocellulose. During the trial, animal performance, whole-body composition and egg quality parameters of hens were consistently ascertained. The results showed that LC-fed hens had lower body weights compared to those receiving CON (p < 0.05). During the laying period, feed intake was increased in LC-fed hens (p < 0.001). LC-fed hens showed a higher egg production and egg mass resulting in an improved feed efficiency (p < 0.05) and laid smaller eggs compared to CON-fed hens (p < 0.001). At 52 weeks of age, bodies of LC-fed hens had higher protein and lower fat contents than those fed with CON diet (p ≤ 0.001). Mean body weight was positively correlated to the body fat content (p = 0.004) and body fat content was negatively correlated to the egg production (p = 0.043). Analyses of the egg quality showed that yolk mass at all sampling points and albumen mass at 27 and 42 weeks were lower in hens fed with diet LC compared to those fed with diet CON (p< 0.05). In conclusion, the feeding of energy- and nutrient-reduced diets containing 10% lignocellulose reduced the body fat content and simultaneously improved the laying performance in dual purpose hens.

Laying performance, digestibility and plasma hormones in laying hens exposed to chronic heat stress as affected by betaine, vitamin C, and/or vitamin E supplementation.

Heat stress had a negative effect on laying hens’ performance, thus this research was to study the influences of betaine (Bet, 1000 mg/kg betaine), vitamin C (VC, 200 mg/kg ascorbic acid), and vitamin E (VE, 150 mg/kg α-Tocopherol acetate) and their possible combinations on egg production, digestibility of nutrients, plasma hormones and reproductive organs of dual-purpose hens exposed to chronic heat stress. Two hundred and eighty eight hens and thirty-six cocks from 32 to 48 weeks of age were divided into nine treatment groups of four replicates, each containing eight hens and one cock. One group was kept under thermo-natural condition and the eight others were kept under chronic heat stress (CHS). One of these eight was used as a negative control, while the others were supplemented with VC, VE and/or betaine and their possible combinations. Body weights, laying rate, feed intake, and feed conversion ratio in hens reared under CHS rooster without any supplementation during 32 to 48 weeks of impairment (P = 0.0052) were recorded. Hens reared under heat stress and fed a diet supplemented with either Bet, VC, VE or combination of the supplements increased production traits. However, hens supplemented with VC showed the greatest production traits. Plasma glucose, estradiol-17 (E2), progesterone (P4), tri-iodothyronine (T3) and thyroxine (T4) decreased in hens reared under CHS and fed a diet with no supplementation compared to the other treatments (P = 0.001). Liver weights, spleen weights, thyroid gland weights, ovary weights, oviduct weights and oviduct lengths were lowest in hens reared under CHS and fed a diet with no supplementation (P = 0.0480). In conclusion, dual purpose hens reared under CHS and supplemented with VC at 200 mg/kg diet and Bet at 1000 mg/kg enhanced the laying performance and combated CHS.

Search for Specific Expressed Genes in Chicken Sperm Storage Tubules by differential Display Polymerase Chain Reaction

The objective of this study was to find the specific expressed genes in chicken sperm storage tubules. One hundred and fifty dual-purpose hens at 30 weeks of age were inseminated with 1 × 108spermatozoa on two consecutive days. Eggs were collected and set daily during the 24 days following the latter of two inseminations. Five hens with fertility below 60% were inseminated with fresh semen. Fifteen hens with fertility above 80% were divided into three groups. Fresh semen, frozen dead semen and 0.9% NaCl, respectively, were injected into the vagina of five hens in each group. RNA from the utero-vaginal junction (UVJ) of the hens was reverse transcribed and differentially displayed. Four bands of interest which were expressed in UVJ from hens inseminated with fresh semen or frozen semen but not from hens inseminated with saline were selected, re-amplified, cloned and sequenced. BLAST search showed that band A is similar to part of chromosome 3 (the homology is 9–8%) and the nearest gene to the fragment is 1,722 base pairs up-stream whose product is mitogen- activated kinase. Band B is similar to phosphatidyl inositol glycan anchor biosynthesis gene (PIGK) and the homology is 98%. PIGK is a subunit of glycosylphosphatidylinositol transamidase (GPI8). GPI-linked proteins participate in the release of membrane proteins. Band F is similar to a hypothetical protein gene and the homology is 9–7%. This hypothetical protein belongs to chicken neurexophilin. Band G is similar to fat3 and the homology is 97%. Neurexophilin and fat3 are proteins that function in the nervous system. Taken together these data indicate that hens may regulate sperm storage in UVJ through the nervous system and may release sperm from the UVJ through GPI8.

Analysis of sperm storage ability using duration of fertility in hens

1. The objective of this study was to determine hens’ sperm storage potential. 2. Efficient duration (De, number of days between insemination and the first clear egg), maximum duration (Dm1, number of days from the day after insemination to the last fertile egg before two consecutive infertile eggs) and maximum duration (Dm2, number of days from the day after insemination to the last fertile egg) of fertility, fertile egg number, egg production, laying rate and fertility during the 24 d following the latter of two inseminations (with 1 × 108 spermatozoa) on two consecutive days were measured in a total of 150 dual-purpose hens at 30 weeks of age. 3. De, Dm1 and Dm2 were 12·06, 14·44 and 16·17 d, respectively, and the three definitions of fertility duration (DF) differed greatly. 4. Significant correlation coefficients between De and Dm1, Dm1 and Dm2, and De and Dm2 were 0·51, 0·57 and 0·23, respectively. 5. We suggest that De and fertile egg number should be used to assess the ability of storing spermatozoa in female fowl.