C. D. McDaniel

Breeder hen dietary L-carnitine affects progeny carcase traits

1. Ross 308 broiler breeder hens were given diets containing 0 or 25 mg L-carnitine/kg from 21 weeks of age. 2. Hens were inseminated with semen from Ross broiler breeder males and subsequent growth performance and carcase traits, of progeny obtained from hatches at 30, 35 and 37 weeks of age, were evaluated. 3. Progeny were hatched in a common facility and separated by gender. Experimental treatments employed for the 30-, 35- and 37-week hatches, respectively, were: hen diet and progeny gender (16 replications with two subplots); hen diet, progeny diet (0 and 50 mg L-carnitine/kg of diet) and progeny gender (16 replications with 4 subplots); and hen diet and progeny diet (high and low density; 16 replications with two subplots). 4. Females had lower growth rate and less breast meat, but greater proportions of carcase fat and breast meat than males. Growth performance measurements of progeny were not affected by hen L-carnitine, but hen L-carnitine decreased abdominal fat in progeny. Increasing diet density in the chick diets increased growth and carcase weights. Hen and progeny dietary L-carnitine interacted to increase male mortality. However, dietary hen L-carnitine decreased carcase fat and increased breast meat in progeny fed on high nutrient density diets. 5. In conclusion, L-carnitine in the diet of hens affected carcase traits of their progeny.

Evaluation of different selective media and culturing techniques for the quantification of Campylobacter ssp. from broiler litter

Poultry is a major reservoir for Campylobacter, the leading cause of foodborne illness in the United States, but how broilers become initially colonized is still under debate. Broiler litter is a potential source, but the best technique for quantifying Campylobacter from litter is still unknown. Therefore, our objectives were to determine if certain media are more selective for quantifying Campylobacter and if enrichment allows for the detection of stressed or viable but nonculturable cells from broiler litter samples. In this trial, 5 media and 2 culturing techniques were used to enumerate Campylobacter from broiler litter. The media used were campy-Line agar (CLA), campy-cefex agar (CCA), modified CCA, Campylobacter agar plates (CAP), and modified charcoal cefoperazone deoxycholate agar. Litter samples were obtained from a commercial broiler house. Each sample was equally divided and diluted 10-fold into peptone, for direct plating, or 4-fold into Campylobacter enrichment broth. Samples diluted in peptone were direct-plated onto each media and incubated under microaerophilic conditions for 48 h at 42 degrees C. Samples diluted in enrichment broth were incubated under the same conditions for 24 h, then further diluted to 10-fold before plating. Plates from enriched samples were incubated for an additional 24 h after plating. After incubation, all plates (direct and enriched) were counted and presumptive positive colonies were confirmed using a Campylobacter latex agglutination kit. Results indicated that there was no difference in the ability of any of the selective media tested to grow Campylobacter. Direct-plated samples had a higher Campylobacter isolation rate compared with enriched samples. The CLA and CAP were able to suppress total bacterial growth better than modified charcoal cefoperazone deoxycholate, modified CCA, and CCA. The CLA and CAP were the only media able to detect total bacterial population shifts over time. In conclusion, it is important before making a final decision on a selective medium to consider the mediums ability to suppress total bacterial growth as well as isolate Campylobacter.

Disinfection of eggshells using ultraviolet light and hydrogen peroxide independently and in combination

Poor hatchability can occur due to eggshell bacterial contamination, which can be decreased by UV light or H(2)O(2) alone. However, antimicrobial effects of these 2 treatments combined, as well as optimum length of UV exposure, are not known. Therefore, the objectives of this study were to determine the optimum length of UV exposure for maximum bacterial reduction and to determine if a greater bacterial reduction would occur using a combination of UV and H(2)O(2) compared with either treatment alone. The first experiment was conducted to determine the optimum length of UV exposure by exposing eggs to 4, 8, 16, and 32 min of UV. Three experiments were also conducted to determine what concentration of H(2)O(2) in combination with UV exposure would yield maximum bacterial reduction. For experiment 2, treatments consisted of a control and UV alone as well as 0, 1, 2, and 3% H(2)O(2) alone and in combination with UV for 8 min. In experiment 3, treatments consisted of a control, UV alone, 3% H(2)O(2) alone, as well as 0, 0.5, 1, 1.5, 2, 2.5, and 3% H(2)O(2) in combination with UV for 8 min. Experiment 4 used 10 treatments including a control and 1.5, 2, and 2.5% H(2)O(2) at UV exposure times of 2, 4, and 8 min for each H(2)O(2) concentration. Results indicated that every control eggshell contained bacteria, resulting in an average bacterial count of 4 log cfu/egg. Exposure to UV alone for 8 min yielded significant bacterial reductions without excessive egg heating. When administered independently, H(2)O(2) and UV each reduced eggshell bacterial counts by 2 log cfu/egg. The combination of 1.5% H(2)O(2) and UV for 8 min reduced bacterial counts by a maximum of 3 log cfu/egg, with only 35% of the eggs positive for bacteria. Because bacterial contamination was further reduced by using a combination of UV and H(2)O(2), it is possible that hatchability and chick quality of breeder eggs might be improved by such treatments.

Effects of breeder hen age and dietary L-carnitine on progeny embryogenesis

1. Ross 308 broiler breeder hens were given diets containing 0 or 25 mg L-carnitine/kg (8 replications per treatment) from 21 weeks of age. 2. Hens were inseminated with semen from Ross broiler breeder males. In a common facility, subsequent progeny hatchability and embryonic mortality at 25, 30, 32, and 38 weeks of breeder age were evaluated. 3. Subsequent egg component weights, incubational egg water loss, progeny embryo growth, and embryo, yolk sac and liver composition through 18 d of incubation at 27, 32, and 38 weeks of breeder age were evaluated. 4. Calculated additions of L-carnitine were in agreement with analysed contents of 3·5 and 31·1 mg free L-carnitine/kg of diet, respectively, and total L-carnitine concentrations increased by 48·6, 21·7, and 10·0% in 0-d yolk, 18-d yolk sac, and 18-d liver samples, respectively, due to the addition of dietary L-carnitine. 5. Supplemental L-carnitine resulted in increased (0·6%) relative 0-d egg yolk weight across weeks 27, 32, and 38, and reduced (0·38%) 18-d yolk sac palmitoleic acid concentration at week 27 without altering embryogenesis. 6. In conclusion, dietary L-carnitine (25 mg/kg of the diet) was deposited in the yolks of broiler breeder hens and was subsequently transferred to the embryonic liver via yolk sac absorption through 18 d of incubation. Furthermore, dietary L-carnitine supplementation increased ovarian follicle yolk deposition in 27-, 32-, and 38-week-old breeder hens, and influenced yolk sac fatty acid β-oxidation in embryos from 27-week-old breeder hens causing yolk sac palmitoleic acid concentrations to be reduced by 18 d of incubation.

Impact of 6 different intestinal bacteria on broiler breeder sperm motility in vitro

Male fertility is often evaluated by measuring sperm parameters, including concentration, viability, and motility. This is important because after copulation occurs, sperm must overcome many barriers in the female reproductive tract to fertilize the ovum. In mammalian species, sperm have been shown to have reduced motility when bacteria are present. In male broiler breeders, bacteria have been associated with spermatozoa, but their effect on motility has not been investigated. The sperm quality index is a modern rapid method of evaluating avian sperm motility. Therefore, the objective of this study was to use the sperm quality index to determine if broiler breeder sperm motility is reduced when semen is exposed to various bacteria. In this experiment, semen was collected from 20 broiler breeders to obtain a pooled neat semen sample. Six different intestinal bacteria, Salmonella enterica, Escherichia coli, Campylobacter jejuni, Clostridium bifermentans, Lactobacillus acidophilus, and Bifidobacterium animalis were cultured overnight. For each bacterium, 50 µL of semen was diluted in 450 µL of saline, sterile broth, or the overnight culture, creating 3 treatments. The experiment was repeated twice. In each treatment, 3 replicates were evaluated at 0 and 10 min postinoculation, creating a completely randomized design with a split plot over time. Also, the pH was measured for each treatment at 0 and 10 min. The results indicated that all broths containing bacteria immediately reduced broiler breeder sperm motility when compared with the controls (P < 0.0001), but broths containing Bifidobacterium or Lactobacillus virtually made sperm immotile. Although broth containing Salmonella, Campylobacter, and Bifidobacterium immediately reduced sperm motility, the reduction did not change over time. Broths containing E. coli, Clostridium, and Lactobacillus reduced sperm motility immediately, but over time motility continued to decrease. However, pH was increased when semen was exposed to the E. coli and Campylobacter treatment, but when semen was exposed to Bifidobacterium and Lactobacillus treatments, pH was reduced. In conclusion, the results indicate that bacteria can reduce broiler breeder sperm motility upon exposure.

Genetic selection increases parthenogenesis in Chinese painted quail (Coturnix chinensis)

Parthenogenesis, embryonic development of an unfertilized egg, occurs naturally in turkey, chicken, and quail species. In fact, parthenogenesis in turkeys and chickens can be increased by genetic selection. However, it is unknown if genetic selection for parthenogenesis is effective in quail or if selection for parthenogenesis affects egg production. Therefore, the objectives of this study were to determine if the incidence of parthenogenesis in quail could be increased by genetic selection and if selection for this trait affects egg production. To prevent fertilization, 1,090 females were caged separately from males at 4 wk of age and then caged individually at 6 wk of age to monitor egg production. Eggs were collected daily, labeled, and stored for 0 to 3 d. After 10 d of incubation, 20 unfertilized eggs from each hen were examined for the occurrence of parthenogenesis and embryonic growth. In the parent (P) generation and subsequent generations (1 to 4), hens laying eggs containing parthenogenetic development and males whose sisters or mothers exhibited parthenogenesis were used for breeding. There was a linear increase in the percentage of hens exhibiting parthenogenesis as generation of selection increased. With each successive generation, there was a quadratic response in the percentage of eggs positive for parthenogenesis. When compared with the P generation, parthenogenesis was almost 3 times greater for eggs laid by the fourth generation (4.6 to 12.5%, respectively). Even when only hens exhibiting parthenogenesis were examined, the percentage of eggs demonstrating embryonic development responded quadratically with generation of selection. The embryonic size at 10 d of incubation was greater for each subsequent generation when compared with the P generation. There was a linear decrease in both egg production and the average position of an egg in a clutch as generation of selection increased. In conclusion, genetic selection for parthenogenesis increased the incidence of parthenogenesis and embryonic size but decreased egg production and average position of an egg in a clutch as generations of selection increased.

Metabolic and hormonal responses of growing modern meat-type chickens to fasting

Abstract 1. The present study compared the effects of fasting on circulating concentrations of glucose, insulin and glucagon in male and female modern meat-type chickens (Ross 708) at three ages (19 d, 33 d and 47 d). 2. Plasma concentrations of glucose were reduced by fasting with reductions of 24.9% (19-d-old), 22.6% (33-d-old) and 17.9% (47-d-old) in broiler chickens fasted for 12 h. 3. Plasma concentrations of insulin decreased with fasting. For instance, circulating concentrations of insulin declined after 6 h of fasting by 45.7%, 54.7% and 50.0%, respectively, in 19-d-old, 33-d-old and 47-d-old broiler chickens. 4. Plasma concentrations of glucagon were increased by fasting. Plasma concentrations of glucagon were elevated by 3.79% (19-d-old), 3.51% (33-d-old) and 3.79% (47-d-old) with 6 h of fasting and remained elevated with 12 h, 18 h and 24 h of fasting.

Dietary influence of digestible lysine concentration on Cobb 500 hen broiler breeder reproductive performance.

A study was conducted to examine the reproductive parameters of Cobb 500 broiler breeder hens fed 2 different types of diets varying in digestible lysine concentration. In total, 240 Cobb 500 broiler breeder pullets were placed in individual cages and given experimental diets from 35 to 45 wk of age. Treatments 1 and 2 were diets formulated using only commercially available feed ingredients and consisted of digestible lysine intakes of 1,200 (IDL) and 1,010 mg/hen per day (ID). Treatments 3 and 4 consisted of semipurified diets with the inclusion of l-glutamic acid to maintain isonitrogenous conditions with digestible lysine intakes of 1,010 (SPL) and 600 mg/hen per day (SP). Hens fed the SPL and SP diets had lower hen-day egg production than hens fed the ID diet, with hens receiving the IDL diet yielding intermediate values. Hens fed the SP diet had the lowest (P < 0.05) egg weight, but no differences were observed among dietary treatments for egg specific gravity. Fertility and hatchability of eggs set were lowest (P < 0.05) for hens fed the SPL dietary treatment. No differences were observed for early and middle embryonic mortality, contaminated, or pipped eggs. Late embryonic mortality was observed to be higher (P < 0.05) in hens fed the SP diet. A decrease in the daily intake of digestible lysine appeared to improve broiler breeder reproductive performance when hens were fed a semipurified diet. In contrast, the same effect was not observed when hens were fed a standard industry-type diet that contained less lysine.

The effects of heat stress and sperm quality classification on broiler breeder male fertility and semen ion concentrations

1. The present study was undertaken to determine the effects of heat exposure on fertility, semen quality, and semen ion concentrations of broiler breeders classified on sperm quality index (SQI) before heat stress. 2. Cobb males (108) were individually caged in 6 temperature-controlled rooms. Each room contained an equal number of males from each of the 4 SQI population quartiles as follows: best (B), good (G), fair (F), and poor (P). Three rooms were heated to 35 ° C, and the other three rooms were maintained at a constant 23 ° C as controls. For each SQI group in each room, 15 Leghorn hens were artificially inseminated (5 × 10 7 sperm/hen) once a week for 8 weeks for fertility observations. 3. Body weight, sperm concentration, SQI, and fertility of P males were lower than in the other three SQI groups. Body temperature of the top three SQI groups was increased by heat exposure, but body temperature was not altered by heat stress in the P group. Fertility, sperm viability, and SQI of the top three SQI groups, but not the P group, was decreased by heat stress. Seminal plasma K + of P males was lower than that of B males. However, seminal plasma Ca 2+ concentration of P males was higher than that of B males. 4. In conclusion, high ambient temperatures had more impact on semen quality and fertility of males in the top 75% of the SQI population than in males in the bottom 25% of the population. In addition, calcium ions (Ca 2+ ) appear to play a major role in heat stress infertility.

The relationship of parthenogenesis in virgin Chinese Painted quail (Coturnix chinensis) hens with embryonic mortality and hatchability following mating1

Unfertilized chicken, turkey, and quail eggs are capable of developing embryos by parthenogenesis. However, it is unknown if the physiological mechanisms regulating parthenogenesis in virgin hens may actually work against fertilization, embryonic development, and hatchability of eggs from these same hens following mating. Additionally, because most parthenogenic development closely resembles early embryonic mortality in fertilized eggs during the first 2 to 3 d of incubation, it is possible that many unhatched eggs classified as containing early embryonic mortality may actually be unfertilized eggs that contain parthenogens. Therefore, the objective of this study was to examine the relationship of parthenogenesis before mating with embryonic development and hatchability characteristics after mating. Based upon their ability to produce unfertilized eggs that contain parthenogens, 372 virgin Chinese Painted quail hens were divided into 7 groups, according to their incidence of parthenogenesis: 0, 10, 20, 30, 40, 50, and greater than 50% parthenogenesis. Males were then placed with these hens so that fertility, embryonic mortality, and hatchability could be evaluated for each hen. Hatchability of eggs set, hatchability of fertile eggs, and late embryonic mortality declined dramatically as the incidence of parthenogenesis increased. On the other hand, early embryonic mortality increased as parthenogenesis increased. Fertility was not different across the 7 parthenogenesis hen groups, perhaps because unfertilized eggs that exhibited parthenogenesis resembled and were therefore classified as early embryonic mortality. In conclusion, virgin quail hens that exhibit parthenogenesis appear to have impaired embryonic development and hatchability following mating. Additional sperm-egg interaction and embryonic research is needed to determine if a large portion of the early embryonic mortality experienced by mated hens that exhibit parthenogenesis as virgin hens is in fact embryonic development in unfertilized eggs.