Peak Egg Production Research Articles

Developing a female-only flock for artificial insemination purposes in ostriches: Progress and future directions

The development of a flock of females that can produce eggs and maintain egg production rate without the presence of males is a prerogative for a viable artificial insemination protocol in ostriches. Over six consecutive breeding seasons (May–December, 2009–2014), we recorded the egg production performance of 40 single-penned (ART) South African Black ostrich females (2–9 years of age), and compared these records with the egg production of 162 pair-mated females of comparable age from the breeding flock (BP). ART females laid significantly fewer eggs than BP females (mean±SEM: 3.49±0.13 eggs per month vs. 4.64±0.09 eggs per month respectively; P<0.001). Both groups showed a similar pattern of laying, with a peak production in July to September. The mean egg weight of ART females was significantly lower than those of BP females (1367±2.25g vs. 1423±1.1g, respectively; P<0.001). Furthermore, female age significantly affected egg production and egg weight whereby BP females reached a peak egg production at 3 years of age, while in ART females, egg production was the highest at 5 years of age. Interestingly, the number of eggs produced, clutches and eggs per clutch of ART females were independent of visual stimulation from the males. These results indicate that male presence is not needed to ensure egg production. Continuous recruitment of young females based on human-friendly behaviour to breeding by artificial insemination from high egg production performance parents could improve egg production of the ART flock. Studies are also needed to gain a better understanding of underlying physiological mechanisms promoting spontaneous ovulation in this species.

ANALYSIS ON DIFFERENT PHASES CYCLE IN PRODUCTION OF LAYING HENS

This study aims to determine the productivity of the eggs produced in each phase of production of laying hens. The research was conducted in the village Bende Wundulako District of Kolaka that lasted approximately one month i.e. October to November 2011. The number of chickens is kept as many as 1,577 animals, strain CP 909. The productivity of egg laying hens is very different. Where in each cycle has increased from the initial production to experience the peak of production, which then slowly decreased. Daily egg production (hen-day production) at an early stage about 18.11%, 87.45% and the peak production of the final phase of 44.75%. While the percentage of egg production average weekly Phase I (17.45%), phase 2 (87.09%) and phase 3 (45.20%), for the production of eggs early (Hen-Housed Production EEG) the initial stage 18, 03%, peak production of 89.84% and 32.17% reject rate. Ties The result shows that the peak of egg production is high both in the production of eggs daily, weekly or early egg production Hen-Housed EEG) average is above 80%. So, it can be concluded that the productivity of egg laying hens are very different. Where in each cycle has increased from the initial production to experience the peak of production, on the cusp of production the number of eggs that produced very high

Phytase and protease supplementation for laying hens in peak egg production

The effects of the combination of enzymes in commercial laying hens need to be more explored in literature. To determine if the type of protease affects performance, egg quality, nutrient intake, and morphometry of intestinal mucosa of laying hens in peak egg production and fed with phytase, 780 25-weeks Hy-Line W36 hens were assigned to a completely randomized design composed of five treatments/diets (one positive control, two negative controls, and negative controls plus protease A or B), with 12 replicates of 13 birds each. There was no effect of treatments (P &gt; 0.05) on egg production, egg mass and feed conversion, even though the nutritional restriction imposed by the negative controls reduced egg weight (P = 0.02), albumen height (P &lt; 0.01), and Haugh unit (P &lt; 0.01). Although inclusion of proteases in negative controls did not cause the calculated intake of protein and amino acids to return to the same amount consumed by positive-control hens, egg quality parameters returned to positive control standards with protease A. Intestinal mucosa responded to treatment only at jejunum, where birds fed with protease B showed greater (P &lt; 0.01) villus height and crypt depth than those treated with protease A. These findings suggest that different proteases and phytases interact distinctly and, in consequence, induce different responses on the birds. Moreover, the behavior of egg quality parameters after protease A inclusion in the diet indicates that the nutritional contribution of the combination of this protease with phytase is greater than the contribution of protease alone.

COMPARATIVE ANALYSIS FOR PRODUCTION TRAITS OF LOCAL CHICKEN AND ISA BROWN IN KGR-IRAQ

The research work has been constructed at Sulaimani Research Station–Director of Agricultural Research to study the effect of three lines of local chickens: Pure black (line 1), Black with brown Neck (line 2), White (line 3) and Isa Brown (line 4) at four periods (19-32, 33-43, 44-60 and 61-75 weeks) on egg production traits. The age at first day of egg production, first week of production, sexual maturity, when reach to 50% and peak egg production and long duration of peak egg production were recorded. In addition to estimate the egg/hen/all periods, egg/hen/week, egg/ hen/ all period% and hen day egg production%. No significant difference between lines on age at first day of egg production, first week of production, sexual maturity and reach to peak production. Line 2 significantly (p<0.05) reach to 50% before other lines about 8-21 weeks. Moreover, line 3 significantly (p<0.05) has the shorter duration of egg production compared with other lines. Hen day egg production% at age at sexual maturity, at 50% production and throughout long duration of production did not significantly differed between lines. Peak production% of line 2 was significantly (p<0.05) higher than other lines. Egg weight was significantly (p<0.05) higher in line 4 compared with lines 1,2 and 3, but did not significantly differed with line 3 in egg/ hen/ all periods and egg/ hen/ week. As for percentage of egg production, line 2 was significantly (p<0.05) higher in percentages (33.20 and 34.30%) for egg/ hen/ periods% and Hen Day Production%, respectively. As the age increased the egg weight was increased, while egg/ hen/ period, egg/ hen/ week and percentage of egg production were significantly (p<0.05) higher at period 3.

Carotenoid accumulation in copepods is related to lipid metabolism and reproduction rather than to UV‐protection

AbstractAccumulation of carotenoid pigments in copepods has often been described as a plastic adaptation providing photoprotection against ultraviolet radiation (UVR). However, reports of seasonal carotenoid maxima in winter, when UVR is low, challenge the proposed driving role of UVR. Therefore, we here evaluate the mechanistic connection between UVR and the seasonal pattern of copepod carotenoid pigmentation. We assessed the carotenoids, fatty acid content and reproduction of Leptodiaptomus minutus along with UVR exposure, water temperature, phytoplankton pigments, and fish predation in a boreal lake during 18 months covering two winter seasons. The predominant carotenoid astaxanthin occurred in free form as well as esterified with fatty acids. Mono‐ and diesters accounted for 62–93% of total astaxanthin and varied seasonally in close correlation with fatty acids. The seasonal variability in total astaxanthin content of the copepods was characterized by net accumulation in late fall of up to 0.034 μg (mg dry mass)−1 d−1, which led to the mid‐winter maximum of 3.89 ± 0.31 μg mg−1. The two periods of net loss (−0.018 μg mg−1 d−1 and −0.021 μg mg−1 d−1) coincided with peaks of egg production in spring and summer leading to minimum astaxanthin content (0.86 ± 0.03 μg mg−1) in fall. This period was also characterized by the highest predation pressure by young‐of‐the‐year fish. The results suggest that accumulation of astaxanthin in copepods is strongly related to lipid metabolism but not to UVR‐photoprotection, and that seasonal changes of fatty acids and carotenoids are related to the reproduction cycle.

Performance of BLRI developed native duck under farmer’s condition with supplementary feeding

A total of 198 straight run day old ducklings of Bangladesh Livestock Research Institute (BLRI) developed native duck (named as Rupali and Nageswary) and local native duck genotypes were distributed among nine farmers of low laying areas of Kalihati Upazilla of Tangail district. Rupali and Nageswary ducklings were obtained from existing stock of BLRI and local native ducklings were collected from local farmers of the study area. After 12 weeks of age each farmers retained 10 female and 2 male ducks and sold away remaining ducklings. Farmers’ were instructed to supply 50g of balanced feed to their ducks in the morning and evening. Ducks were allowed to scavenge in the beel throughout the day. Data on: growth, feed intake, age at onset of lay, egg production rate, egg weight, mortality rate were recorded and cost-benefit was calculated. There found no significant difference on growth parameters, live weight gain, age at first laying or age at peak egg production among the duck genotypes. In the study highest live weight gain was found in Nageswary (1090 g) followed by Rupali (1058 g) and local native (912 g) duck at 8 weeks of age. Egg production rate of local native ducks (37.21%) was found significantly lower (P&lt;0.001) compared to Rupali (50.67 %) and Nageswary (55.40 %). The mortality rate in local duck was significantly higher (P&lt;0.05) compared to Rupali and Nageswary ducks. Rupali ducks produced heavier eggs (66.86g) followed by local native (62.20g) and Nageswary (57.22g) which differed significantly (P&lt;0.05). Rupali ducks laid eggs of thicker shell (0.61mm) compared to other duck genotypes under study which was also varied statistically (P&lt;0.05). Cost benefit analysis shows that earning both from Nageswary and Rupali was much higher than local native ducks. Higher egg production rate of Nageswary and Rupali duck has contributed for higher return. It is concluded that rearing Rupali or Nageswary ducks in the low laying rural areas with scavenging and supplementary feeding facility is more profitable than rearing local native ducks.Bangladesh J. of Livestock Res. 19(1-2): 18-23, Jan-Dec 2012

Evaluation of Performance of Different Japanese Quail (Coturnix Coturnix Japonica) Varieties

The study was conducted to assess three varieties (CARI, PES and WB) of Japanese quails (Coturnix Coturnix Japonica) during the growing and laying periods. In this trail, 360 quails consisting of three varieties each 120 quails were distributed in three treatments with six replicates each consist of 20 chicks. The diets were prepared iso-nitrogenous and iso-caloric. The performance and egg production parameters were studied from 0 to 22 weeks of age. There were no significant differences (P> 0.05) found on body weight gain, feed consumption and feed conversion ratio among varieties from 0 to 6 weeks. The age at first egg was found to be early in the CARI variety 43days. The peak egg production level (79.83±0.64%) during fourth laying cycle in the PES at the age of 18–22 weeks followed by CARI (71.62±0.62%) and WB (49.28±0.43%). The results of the present study indicated that, the three varieties performance and production were significantly there was no difference.

Evaluation of a three-way cross chicken developed for backyard poultry in respect to growth, production and carcass quality traits under intensive system of rearing

ABSTRACTObjective of the work was to develop a three-way cross for egg-type backyard chicken using male and female lines developed from exotic chickens. To improve the egg production further and to get colour plumage pattern, the two-way cross PD1 X IWI males were crossed with PD3 females to produce three-way cross (PD1 X IWI X PD3). The crossbred was evaluated for different traits upto 72 weeks of age. Sexual dimorphisms were evident from two weeks onwards for body weights and shank length differ significantly (P < .05) between male and female at 8, 12 and 16 weeks of age. Male were reared upto 16 weeks of age, and at 16 weeks, body weight of male and female were 1670 and 1096 g, respectively. Carcass quality measured at 16 week of age recorded 66.12% eviscerated carcass yield, 4.84% giblet and 0.30% abdominal fat. Egg production performance recorded from 17 to 72 weeks of age at 4 weeks interval showed significant (P < .05) difference between different periods, and peak egg production was recorded during 29–32 weeks. At 69–72 weeks period, the egg production per bird was 14.78 eggs. Egg production upto 40, 52, 64 and 72 weeks of age were 91.71, 105.84, 204.88 and 233.28 eggs, respectively. Age and weight at sexual maturity were 163.14 days and 1702 g, respectively. Egg weight recorded at 4 weeks interval starting from 20 weeks of age showed linear increase upto 56 weeks of age with significant differences at different ages. The results indicate that the cross may be of use for egg-type poultry in the backyard. However, before large-scale propagation, the cross has to be evaluated in the field.

Rare earth element-enriched yeast improved egg production and egg quality in laying hens in the late period of peak egg production.

The objective of this study was to determine the effects of rare earth element-enriched yeast (RY) on egg production, coefficient of total tract apparent digestibility (CTTAD), egg quality, excreta gas emission and excreta microbiota of laying hens. A total of 216 ISA brown laying hens of 52weeks of age were used in a 5-week feeding trial and data were collected every week. Birds were randomly allotted to three dietary treatments each with six replicates and 12 hens per replicate. Each cage (38cm width×50cm length×40cm height) contained one hen. Treatments consisted of corn-soya bean meal-based diet supplemented with 0, 500 or 1000mg/kg of RY. From weeks 55 to 56, inclusion of RY linearly increased (p<0.05) egg production. The CTTAD of nitrogen was increased (linear, p<0.05) with increasing dietary level of RY. In week 55, yolk height and Haugh units were increased linearly (p<0.05) with increasing dietary RY content. However, no significant effects were observed in terms of excreta emissions and excreta microbiota in laying hens. In conclusion, dietary supplementation with RY improved egg production and CTTAD of nitrogen and slightly improved egg quality in laying hens of the late period of peak egg production.

Vitamin E and selenium in broiler breeder diets: Effect on live performance, hatching process, and chick quality

This study evaluated the effect of different dietary vitamin E levels and different selenium sources on the productive and reproductive performance of broiler breeders. In total 640 females and 64 males between 22 and 52 weeks old were studied. A completely randomized experimental design in factorial arrangement, with 4 treatments of 8 replicates with 20 females and 2 males each, was applied. Treatments consisted of 2 vitamin E levels (30 and 120 mg/kg) and two selenium sources (sodium selenite and zinc-L-selenomethionine). Egg production (rate of lay and eggs per breeder), egg characteristics (egg, yolk, eggshell, and albumen weights), fertility, incubation responses (egg weight loss during incubation, hatchability, and hatching window), and hatchling characteristics (weight and yield) were evaluated. There was no influence of dietary vitamin E levels or selenium sources on egg production (P > 0.05). Mature breeders (47 weeks old) fed zinc-L-selenomethionine and 120 mg vitamin E/kg feed produced heavier eggs and albumen. Hatchability of the eggs of breeders fed 120 mg vitamin E/kg feed was higher than breeders fed 30 mg vitamin at 29 wks. The dietary inclusion of organic selenium also promoted heavier hatchling weight until egg production peak (33 wk), but did not influence hatchling quality or hatching window. It was concluded that the dietary supplementation of zinc-L-selenomethione and vitamin E (120 mg/kg feed) could be used to improve egg characteristics and incubation response.

Palm Kernel Meal and Brewer's Dried Grain Improve Laying Performance of Japanese Quails (Coturnix Coturnix Japonica) without Affecting Egg Quality Characteristics

This study was carried out to evaluate the laying performance and egg quality characteristics of Japanese quails (Coturnix coturnix japonica) fed palm kernel meal (PKM) and brewers dried grain (BDG) based diets. Five diets were formulated with diet 1 (control) containing 0%PKM and 0%BDG. PKM and BDG were included at two levels each in diets 2, 3, 4 and 5 respectively (15%PKM, 30%PKM, 15%BDG and 30%BDG). A total of 150 Japanese quail (point of lay) of six-weeks old were allotted to five dietary treatment groups of 30 quail birds each with three replicates of 10 birds per pen in a completely randomized design. The diets were formulated to be isonitrogenous (22%CP). The birds were raised in cages for sixteen weeks. Water and feed were offered ad libitum. The result of the experiment showed that there were significant (P 0.05) differences in daily weight gain, egg production and egg weight across the treatment groups. Peak egg production was significantly (P 0.05) difference across the treatments when compared with the control. Thus, utilization of BDG and PKM in quail’s diet at 30% inclusion level during the egg laying phase resulted in enhanced growth and egg production performance at the least cost.

Anaerobic spirochaetes and animals

Anaerobic spirochaetes colonise the large intestine of many avian and mammalian host species. The most well known pathogenic species is the strongly haemolytic Brachyspira hyodysenteriae that was first isolated from pigs with swine dysentery (SD) in the early 1970s. Classical SD is a severe mucohaemorrhagic colitis that occurs in growing pigs and is endemic in most pig-rearing areas of the world. The spirochaete acts in concert with other components of the colonic microbiota to disrupt the integrity of the colonic epithelium and induce inflammation. In recent years two new strongly haemolytic species, the proposed ‘Brachyspira suanatina' and ‘Brachyspira hampsonii', both with reservoirs in migratory water birds, have been described as new and emerging agents of SD in the northern hemisphere. Weakly haemolytic species also have been described, some of which have pathogenic potential. In particular Brachyspira pilosicoli causes a mild colitis and diarrhoea in many species, including human beings, whilst Brachyspira intermedia is a common pathogen in adult poultry. Infection with B. intermedia and/or B. pilosicoli can cause wet litter, faecal staining of eggshells and delays in reaching peak egg production. Options for control of these widespread and economically significant anaerobic infections are limited.

Pathomorphological studies of polyserositis in commercial caged layer chicken

ObjectiveTo detect etiological agents and pathological changes associated with polyserositis in commercial layer chicken. MethodsTen commercial layer flocks which had a sudden increase in mortality and a drop in egg production with lesions suggestive of colisepticemia were investigated. Flock details and pathological changes were recorded in affected flocks to assess the prevalence and impact of polyserositis on commercial layer chicken. Trachea, heart blood, liver, oviduct, cloacal swab, poultry house environment samples, water and feed samples were screened for bacteriological agents. Pooled tissue (trachea, lung, spleen, caecal tonsil, kidney and oviduct) samples from colisepticemia cases were screened for viral agents. Serum samples collected from affected flocks were screened for Newcastle disease virus, infectious bronchitis virus and egg drop syndrome-76 virus by haemagglutination inhibition test, and for Mycoplasma gallisepticum and Mycoplasma synoviae by enzyme linked immunosorbent assay. ResultsOn necropsy examination of dead birds, fibrinous polyserositis and congestion of various visceral organs were noticed. Microscopically, deciliation and hypertrophy of mucus glands showed in the tracheal epithelium. Vascular derangements and infiltration of inflammatory cells showed in the lungs and air sac. Fibrinous polyserositis, focal necrosis and infiltration of inflammatory cells showed in parenchyma of heart and liver. Inflammatory changes were observed in the ovary and oviduct. Escherichia coli (E. coli) was isolated as a pure culture from 108 birds and from the poultry house environment of the ten affected flocks. Among the eight E. coli serotypes, identified serotypes O78 and O111 were predominant. In colisepticemia affected flocks egg production drop and mortality varied from 3%-10% and 2%-5%, respectively and occured during the peak egg production (21 to 40 weeks) and southwest monsoon season (June to September). ConclusionsThe present study revealed that the colisepticemia inducing E. coli isolates were derived from the layer house environment. Hence, the incidences of colisepticemia can be minimized by effectively reducing the bacterial load in the layer house environment through appropriate biosecurity measures.

Effects of live and killed vaccines against Mycoplasma gallisepticum on the performance characteristics of commercial layer chickens

Different vaccine strains of Mycoplasma gallisepticum have been used on multiple-age commercial layer farms in an effort to protect birds against virulent field-strain infections. Use of the F-strain of M. gallisepticum (FMG), as an overlay vaccine during lay, may be necessary because of the lower level of protection afforded by M. gallisepticum vaccines of low virulence given before lay. Two replicate trials were conducted to investigate effects of live and killed M. gallisepticum vaccines administered individually and in combination before lay, in conjunction with an FMG vaccine overlay after peak egg production (EP), on the performance characteristics of commercial layers. The following treatments were utilized at 10 wk of age (woa): 1) control (no vaccinations); 2) ts11 strain M. gallisepticum (ts11MG) vaccine; 3) M. gallisepticum-Bacterin vaccine (MG-Bacterin); and 4) ts11MG and MG-Bacterin vaccines combination. At 45 woa, half of the birds were overlaid with an FMG vaccine. Hen mortality, BW, egg weight, percentage hen-day EP, egg blood spots, and egg meat spots were determined at various time periods between 18 and 52 woa. The data from each trial were pooled. Treatment did not affect performance in interval I (23 to 45 woa). However, during interval II (46 to 52 woa), the EP of control and MG-Bacterin-vaccinated birds that later received an FMG vaccine overlay was lower than that in the other treatment groups. Furthermore, treatment application reduced bird BW during interval II. Despite the effects on BW and EP, no differences were observed for egg blood or meat spots among the various treatments. It is suggested that the vaccination of commercial layers before lay with ts11MG, but not MG-Bacterin, may reduce the negative impacts of an FMG overlay vaccination given during lay. These results establish that the vaccination of pullets with ts11MG in combination with the vaccination of hens with an FMG overlay, for continual protection against field-strain M. gallisepticum infections, may be used without suppressing performance.

Effects of feeder space allocations during rearing, female strain, and feed increase rate from photostimulation to peak egg production on broiler breeder female performance

A study was conducted to determine if there were differences in female broiler breeder performance of 2 strains that had been subjected to 2 feeder space allocations during the growing period followed by 2 feeding to peak programs. Ross 308 and 708 pullets were reared with a single feeding program to 23 wk of age and with 2 circumferential feeder space allocations (5.3 cm/female or 7.0 cm/female) and then assigned to 2 feed increase programs (slow or fast) from photostimulation to peak egg production. The flock was moved to the laying house with 8.8 cm/female of female feeder space and photostimulated at 23 wk of age when Ross 344 males were added to create 16 pens with 60 females and 7 males each in a 2 × 2 × 2 design. The fast feed increase program significantly increased female BW at 31 wk of age, which could have contributed to an increased female mortality during the summer weather of early lay. The 708 females with 5.3 cm/female feeder space produced smaller eggs at 28 and 30 wk of age. The 708 females exhibited better fertile hatchability than 308 females due to fewer late dead embryos. There were no differences in egg production, fertility, or fertile hatchability due to the main effects of feeding to peak program or growing feeder space, but the slow feed increase from photostimulation to peak production reduced cumulative mortality.

Laying performances and egg quality of local barred hens under improved conditions in Cameroon

Objectives: This study was designated to evaluate the laying performances and egg traits in local barred hens. Sixteen (16) hens and 4 cocks were used, divided into 4 experimental units of 4 hens and 1 cock per unit.Methodology and Results: The following parameters were studied: feed intake (g/bird/day), egg production (%/hen-day), egg weight (g), egg mass (g/hen/day), feed conversion ratio (g feed/g egg) and egg cost (Fcfa). A total of 730 eggs were used to evaluate external egg traits including egg weight, egg length, egg width, egg index and 320 eggs to evaluate internal egg traits including relative yolk weight (%), yolk height, yolk diameter, relative shell weight (%), shell thickness, albumen height, relative albumen weight (%) and haugh unit. Mean values for laying performances were: age at first egg (22.5 weeks), hen live weight at first egg (1298g), hen age at peak egg production ( 33 weeks), percent egg production at peak (57.9%), feed conversion ratio (5.36), mean egg production (40.4%) and egg cost (48.5 Fcfa). Mean egg traits were: egg weight (43.8g), relative albumen weight (17.3%), albumen height (5.74mm), haugh unit (78.0), relative yolk weight (34.9%), relative shell weight (11.6%) and shell thickness (25.9mm). There was a highly significant (P&lt;0.01) correlation between egg weight, yolk volume and albumen volume. This correlation was weak between egg weight and albumen height (0.060) and egg weight and shell thickness (0.020).Conclusions and applications of findings: The present study suggests that local barred hens have a good potential for egg production, which may be useful for breed improvement, and development for future generation of local laying hens.Key words: egg quality, laying performances, local barred hens.

Bacteriological and pathological studies of egg peritonitis in commercial layer chicken in Namakkal area

ObjectiveTo detect the various bacteriological agents and pathological changes in commercial layer chicken affected with egg yolk peritonitis in Namakkal region of India. MethodsA total of 6 572 layer chicken from 85 commercial farms were subjected for the study, out of which 1 715 showed various types of oviduct abnormalities. Among the 1 715, 264 birds from six farms were identified as egg peritonitis on the basis of postmortem examination. Trachea, lung, heart blood, liver, peritoneal exudate, oviduct (infundibulum, magnum, uterus) and cloacal swabs were collected from the 264 birds with egg peritonitis lesion for screening of bacterial agents. Signalment, clinical signs and pathological changes were recorded in the affected flocks. ResultsThe results of the present investigation indicated that the E. coli associated egg peritonitis was responsible for 15.39% of the reproductive tract abnormalities in commercial layers between 21 and 80 week of age. In the affected flocks egg production drop and mortality varied from 3% to 20% and 0.5% to 7.0% respectively. It was noticed during peak egg production (21 to 60 week) and southwest monsoon season (58%). Statistical analysis of age, season and egg production by Chi square test of independence revealed highly significant difference. E. coli was isolated as a pure culture and concurrent with other bacterial agents in 226 and 38 birds respectively. Among the fifteen E. coli serotypes identified serotype O166, O64 and O111 were predominant. Necropsy examination of affected birds revealed the presence of amorphous or insipissiated yolk material in the abdominal cavity with inflammatory changes in the ovary, oviduct and intestine. Microscopically the oviduct surface epithelium showed degeneration and desquamation, moderate to marked infiltration of inflammatory cells especially heterophils and lymphocytes in various regions and lumen contained serofibrinous exudate, inflammatory and desquamated epithelial cells with bacterial microcolonies. Ovarian follicles revealed hyperemia, degeneration of granulosa cells and infiltration of inflammatory cells. Intestine showed degenerative, necrotic and inflammatory lesion. ConclusionThe findings of this study showed that the egg peritonitis might be caused by either the translocation of intestinal E. coli into the peritoneal cavity or by the movement of cloacal E. coli into the oviduct followed by ascension of these bacteria up the oviduct, through the infundibulum, and into the peritoneal cavity. To control the egg peritonitis faecal contamination with E. coli should be minimized.

Effect of Coronavirus Infection on Reproductive Performance of Turkey Hens

Turkey coronavirus (TCoV) infection causes enteritis in turkeys of varying ages with high mortality in young birds. In older birds, field evidence indicates the possible involvement of TCoV in egg-production drops in turkey hens. However, no experimental studies have been conducted to demonstrate TCoV pathogenesis in turkey hens and its effect on reproductive performance. In the present study, we assessed the possible effect of TCoV on the reproductive performance of experimentally infected turkey hens. In two separate trials, 29- to 30-wk-old turkey hens in peak egg production were either mock-infected or inoculated orally with TCoV (Indiana strain). Cloacal swabs and intestinal and reproductive tissues were collected and standard reverse-transcription PCR was conducted to detect TCoV RNA. In the cloacal swabs, TCoV was detected consistently at 3, 5, 7, and 12 days postinoculation (DPI) with higher rates of detection after 5 DPI (> 90%). All intestinal samples were also positive for TCoV at 7 DPI, and microscopic lesions consisting of severe enteritis with villous atrophy were observed in the duodenum and jejunum of TCoV-infected hens. In one of the trials TCoV was detected from the oviduct of two birds at 7 DPI; however, no or mild microscopic lesions were present. In both experimental trials an average of 28%-29% drop in egg production was observed in TCoV-infected turkey hens between 4 and 7 DPI. In a separate trial we also confirmed that TCoV can efficiently transmit from infected to contact control hens. Our results show that TCoV infection can affect the reproductive performance in turkey hens, causing a transient drop in egg production. This drop in egg production most likely occurred as consequence of the severe enteritis produced by the TCoV. However, the potential replication of TCoV in the oviduct and its effect on pathogenesis should be considered and further investigated.

The effect of increasing feeding frequency on performance, plasma hormones and metabolites, and hepatic lipid metabolism of broiler breeder hens

An experiment was conducted to study the effects of feeding regimens on reproductive performance, plasma hormone and metabolite levels, and hepatic lipid metabolism of Cobb 500 broiler breeder hens from 26 to 38 wk of age. Seventy-two birds were used in a completely randomized design with 3 treatments, each replicated 4 times. Treatments were as follows: 1) once a day feeding, in which birds were fed once a day at 0615 h (control), 2) twice a day feeding, in which daily allocated feed was fed in 2 equal meals at 0615 and 1215 h, and 3) thrice a day feeding in which daily allocated feed was offered in 3 equal meals at 0615, 1215, and 1815 h. Through 38 wk of age, total hen-day egg production in the hens fed twice and thrice a day was greater (67.1 and 67.2 vs. 62.2 eggs/hen, P < 0.01). Similarly, egg weight was higher (P < 0.01) in birds fed more than once a day. Multi-meal-fed birds had significantly lower plasma triiodothyronine and glucose at 32 wk and also lower glucose and cholesterol, and higher 17β-estradiol levels at 38 wk than those fed once a day (P ≤ 0.05). Hepatic expression of malic enzyme, fatty acid synthase, acetyl-CoA carboxylase, and ATP citrate lyase relative to β-actin decreased (P < 0.05) in birds fed twice and thrice a day compared with birds fed once a day at peak egg production (32 wk). In contrast, feeding regimens did not affect the hepatic gene expression of lipogenic enzymes after peak egg production at 38 wk. Stearoyl-CoA desaturase 1 (SCD1) gene expression was constant over dietary regimens. There was no difference in malic enzyme activity in multi-meal-fed birds at 38 wk. In summary, feeding broiler breeder hens 2 or 3 meals per day improved the reproductive performance during the early lay cycle. Implementing twice or thrice a day feeding regimens altered hepatic lipogenic gene expression in broiler breeder hens only at peak egg production, which indicated a short-term effect of increasing feeding frequency on hepatic lipid metabolism.

Parâmetros genéticos da curva de produção de ovos de uma linha fêmea de frango de corte

Objetivou-se com este trabalho estimar os parâmetros genéticos e fenotípicos dos parâmetros da curva de produção de ovos, pelo o modelo de polinômios segmentados ("x p"- idade das aves ao pico de postura, "P"- nível de produção no pico, "s" - taxa de decréscimo semanal na produção de ovos após o pico e "t" - tempo entre o início da postura e o pico de produção de ovos). Foram utilizados dados da produção de ovos semanal da 25ª até 64ª semanas de idade, provenientes de 2.398 matrizes de uma linhagem de frangos de corte. A estimação dos componentes de covariâncias, herdabilidade e correlações para esses parâmetros da curva de postura foram obtidas por máxima verossimilhança restrita. As tendências genéticas foram estimadas com as médias dos valores genéticos dos parâmetros da curva em função do ano de nascimento das matrizes. As médias das herdabilidades foram de baixa a média magnitudes, 0,25 (x p), 0,18 (P), 0,17 (s) e 0,10 (t). As correlações genéticas entre o parâmetro t e os demais parâmetros da curva foram positivas, variando de 0,21 até 1,00, sendo menor entre t e s e maior entre os parâmetros x p e t. Entre os parâmetros x p e P, a correlação também foi positiva, de magnitude média (0,39). As correlações foram negativas entre os parâmetros s e x p e s e P, apresentando-se menor entre s e x p (-0,17) e maior entre s e P (-0,91). As tendências genéticas encontradas para os parâmetros indicaram uma redução no tempo entre o início e pico de produção e idade ao pico de postura. O nível de produção apresentou uma queda no valor genético ao longo do período avaliado. Pode-se observar possível ganho genético para os parâmetros da curva de produção de ovos, contudo, deve-se atentar para as correlações genéticas positivas entre os parâmetro x p e P, o que pode levar a um aumento do nível de produção e a um aumento na idade ao pico de produção. O mesmo caso acontece com os parâmetros x p e s, indicando que as aves mais precoces ao pico poderão apresentar menor persistência.