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At least 199 records · Page 11Linked to original sources
PubMed1982

Endocrine profiles and embryo quality in the PMSG-PGF2alpha treated cow.

Plasma progesterone and LH concentrations around estrus were determined for both PMSG treated (experimental animals) and non-treated (control animals) dairy cows and heifers of the Holstein Friesian and Jersey breeds, and these hormone profiles were related to the embryo quality. Most experimental animals experienced an increase in progesterone concentrations following PMSG treatment and an abrupt decrease to values below 3 nmol/l after PG injection. The mean (+/-SE) intervals from prostaglandin treatment to estrus were 46.9+/-1.8 h and 64.5+/-4.8 h for experimental and control animals, respectively. At the onset of heat the progesterone concentration in experimental animals with optimal embryo quality (group I) was significantly lower (p<0.01) than in experimental animals which yielded unfertilized eggs (group II) (1.2+/-0.1 versus 3.9+/-0.8 nmol/l) and significantly higher than the level in the control group (0.6+/-0.1 nmol/l). Following estrus the progesterone profiles in all 3 groups were studied and the length of the superovulatory cycle was measured to 26.0+/-4.8 days. The preovulatory LH surge occurred sooner after prostaglandin injection in experimental (41 h) than in control animals (65 h). The LH surge in group I occurred within a narrow range and reached a higher average level than group II (24.2+/-2.2 ng/ml and 16.3+/-3.7 ng/ml, respectively). The control group attained an even higher LH surge (31.8+/-8.8 ng/ml) than did the experimental animals. The data presented in this experiment indicate that plasma levels of progesterone and LH in PMSG-PGF2alpha treated animals are related to embryo or egg quality.

Journal Article↗
PubMed1995

Evaluation of a layer diet formulated from non-conventional feedingstuffs.

1. A layer diet, the formulation of which was based on several non-conventional feedingstuffs, was evaluated at the research station and under small farm conditions in Sri Lanka. The new feedingstuffs included finger millet, rice polishings, rubber seed meal, cassava leaf meal, ipil ipil leaf meal and dried poultry manure. A commercial mash, that is normally used on the farm, served as the control. 2. The performance and egg quality characteristics were similar between the test and control diets, the only exception being the egg yolk colour which was improved (P < 0.05) by feeding the test diet. Food cost per dozen eggs was lowered by feeding the test diet. 3. It is possible to formulate layer diets using non-conventional feedingstuffs, achieve acceptable production and lower the food costs under small farm conditions in tropical developing countries.

Animal Feed↗
PubMed1983

The effects of geographical area, rearing method, caging density, and lymphoid leukosis infection on adult performance in egg stocks of chickens.

Birds were brooded reared, and laying house-tested at two widely separated sites: Animal Research Centre (ARC) and North Central Region Poultry Breeding Laboratory (NCRPBL). Two strain and a commercial stock were included only at NCRPBL. At ARC, all birds were brooded, reared, and laying house-tested in cages. At NCRPBL, half of the chicks were brooded and reared on floor and half in cages, and all hens were laying tested at one or two birds per cage. Most hens housed one per cage were tested for lymphoid leukosis virus (LLV) infection by the complement fixation test for group specific antigen in egg albumen. When all hens tested at NCRPBL were considered, the method of brooding and rearing affected only egg weight and body weight in favor of the hens reared in floor pens. The commercial stock and the strain crosses performed better than the control strains. Despite very similar genetic backgrounds, there were large differences between control strains 10 and NCR. Hens housed one per cage had lower mortality and higher egg production than those housed two per cage. Average performance of birds at ARC was somewhat better than that at NCRPBL, but there were genotype-site interactions for mortality, egg production, and sexual maturity. The frequency of shedders in the crosses (17.2%) was the same as that of the control strains (20.8%), but the frequency of shedders in the commercial stock (4.5%) was much lower. The method of brooding and rearing had no effect on the frequency of shedders. The LLV infection was associated with significant reductions in egg production and egg quality. For example, the difference between test-positive and test-negative hens was 25 eggs per hen housed and 16 eggs per surviving hen.

Animal Husbandry↗
PubMed2005

Performance of indigenous, Khaki Campbell and their reciprocal crossbred layer ducks under different management systems.

1. The performance of indigenous ducks (ID), Khaki Campbell (KC) and their reciprocal crossbred layers was studied from 19 to 58 weeks of age. For each genotype, 4 x 18 ducks (3 males + 15 females) were reared under a semi-intensive system (SIS) and an intensive system (IS) with standard management, and 4 x 50 ducks (8 males + 42 females) were reared in an extensive system (ES) with traditional management. 2. In comparison to KC, ID were superior in terms of age at first egg, age at 50% egg production, egg weight, hatchability, eggshell thickness with higher egg shape index. KC ducks were superior to ID in body weight, egg production and feed/kg eggs. Egg quality was similar among the genotypes. Crosses were superior to their parent breeds in age at first egg, egg production and feed/kg eggs. They were also superior to KC in egg weight and egg-shell thickness with a higher egg shape index. 3. The performance of genotypes in the SIS and the IS was similar and superior to the ES except for fertility and yolk colour. 4. Significant heterotic effects were recorded for age at first egg, age at 50% egg production, egg production per duck-day, feed efficiency and egg weight in crosses. Performance was similar in the reciprocal crosses, but superior to their parent breeds.

Age Factors↗
PubMed2000

One-generation divergent selection on large and small yolk proportions in a White Leghorn line.

1. A striking change in egg consumption from shell eggs toward egg products is taking place. Consequently, internal egg quality traits must be seen in a different light, as they may affect the profitability of the egg processing industry. In order to study the possibility of using breeding as a means to alter yolk production, a one-generation divergent selection experiment was set up. The trait was yolk proportion. The effect of hen's age on egg composition was also studied. Genetic parameters for yolk proportion, yolk weight, egg weight and albumen weight were estimated, using a multiple trait animal model, and restricted maximum likelihood. 2. Selection response was obtained for yolk proportion and correlated selection responses for yolk weight and albumen weight. In the 'high line' a decrease in egg weight and an increase in yolk weight was established, whereas in the 'low line', egg weight remained more or less the same and yolk weight decreased slightly 3. Yolk proportion, yolk weight, egg weight and albumen weight all increased with increasing age of the hen in both selection lines. The difference between selection lines in yolk proportion, yolk weight and albumen weight persisted throughout the laying period. 4. Estimated heritabilities for yolk proportion, yolk weight, egg weight and albumen weight were 0.38, 0.22, 0.34 and 0.41 respectively. The genetic correlation between yolk proportion and yolk weight was 0.52, whereas the genetic correlations with egg weight and albumen weight were -0.51 and -0.74 respectively. 5. We conclude that selection can be used to alter yolk production. Selection can be at an early age with a sustained effect throughout the laying period.

Age Factors↗
PubMed1999

Experimental demonstration that offspring sex ratio varies with maternal condition.

Sex ratio theory predicts that, if prevailing ecological or social circumstances differentially influence the fitness benefits of offspring of each sex, parents should adjust their production accordingly to maximize fitness. For species in which sex is chromosomally determined, such as birds and mammals, a differential effect of maternal condition on the fitness of male and female young is one important route whereby selection is expected to favor a bias in the offspring sex ratio at birth or egg laying. However, despite its central place in sex allocation theory, this hypothesis has rarely been tested in wild populations. We manipulated maternal condition upward and downward in a sexually dimorphic wild bird and examined the effect on offspring survival and on offspring sex ratio. The survival to fledging of male, but not female, young was substantially reduced if they came from less well provisioned eggs produced by females in relatively poor condition. As female condition, and thereby her capacity to produce high quality eggs, declined, she progressively skewed the sex ratio of her eggs toward females; i.e., she produced more of the sex with the higher survival prospects. The decline in the survival of male offspring, and the sex ratio bias, was removed when maternal condition was enhanced. These results provide experimental evidence of an adaptive, facultative adjustment of sex ratio in response to changes in maternal condition in wild birds.

Adaptation, Biological↗
PubMed1995

Effects of cage population on the productive performance of layers.

Two commercial layer strains (3,456 hens total) were used to examine the effects of bird population on productive performance. Four cage population sizes (6, 8, 12, and 24 birds per cage) were compared. All cages were 35.7 cm deep and varied in width (61.2, 81.6, 122.4, and 244.8 cm). Floor space per bird was 364.1 cm2 and feeder space per bird was 10.2 cm in each cage configuration. Egg production and egg quality were measured from 20 to 72 wk of age. Strain differences were detected in hen-day egg production, egg mass, feed consumption, cracked egg percentage, Grade A eggs, Grade B eggs, peewee eggs, and large egg yield. There were no interactions between strain and cage population size. Cage population had no influence on hen-day egg production, mortality, feed conversion, egg size (peewee, small, medium, large, extra large), egg mass, lost eggs (by meat or blood spots), and percentage Grade B eggs. Percentage Grade A eggs, cracked egg percentage, and feed consumption were significantly influenced by cage population size. Hens housed at eight birds per cage had a greater percentage of Grade A eggs and a lower percentage of cracked eggs than those at other populations. Feed consumption was significantly greater for hens housed at 12 and 24 birds per cage compared with those at 6 and 8 birds per cage, respectively.

Animals↗
PubMed1987

Effects of feeding mature White Leghorn hens diets that contain deoxynivalenol (vomitoxin).

Mature White Leghorn hens that had been fed a commercial laying diet were changed to a wheat-based diet over a period of 42 days. Two groups were formed based on equivalent egg production and body weights and randomly assigned to either a control (noncontaminated) wheat diet or a naturally contaminated deoxynivalenol (DON, vomitoxin) wheat diet (18 mg DON/kg). Hens were provided their respective diets and water ad libitum for 112 days along with 16 hr of light. The DON-contaminated diet did not significantly influence hen body weights, hen day egg production, egg weights, or efficiency of feed utilization. Internal egg quality, as measured by albumin height, was slightly, although significantly, improved by feeding the DON-contaminated wheat diet. Egg shell weight and percent egg shell were slightly, although significantly, decreased by feeding the DON-contaminated diet, whereas shell thickness was not altered. No deleterious effects were observed in fertility, hatchability, or chick weights at hatch. The results indicate that laying hens are affected only slightly when fed naturally contaminated wheat diets containing approximately 18 mg DON/kg for 112 days.

Animals↗
PubMed2002

Drinking water temperature effects on laying hens subjected to warm cyclic environments.

Two experiments were conducted to evaluate the effects of drinking water temperature (Tw) on laying hens subjected to warm cyclic air temperature (Ta) conditions. Each experiment consisted of a 1-wk acclimation under thermoneutrality (TN) (Ta = Tw = 21 C), a 4-wk heat exposure or treatment period, and a 2-wk recovery under TN. Each experiment involved 24 individually caged hens at the initial age of 29 wk (Experiment 1) or 30 wk (Experiment 2). In Experiment 1, Tw of 18 or 27 C was provided to 12 birds per Tw regimen under a diurnal Ta of 27 to 35 C (daily mean of 31 C). In Experiment 2, Tw of 15, 19, 23, or 27 C was provided to six birds per Tw regimen under a diurnal Ta of 27 to 38 C (daily mean of 32.5 C). Experiment 1 showed that Tw of 18 C enhanced hourly and daily feed and water intake during the first 2 wk of heat exposure, as compared with Tw of 27 C. Experiment 2 showed that daily feed and water intake were greatest for hens in the 23 C Tw regimen and least for hens in the coolest or warmest Tw regimens. Reduction in daily feed intake with increase in daily mean Ta ranged from 2.0 to approximately 3.2 g/C-day (first week of heat exposure) to 1.1 to approximately 1.9 g/C-day (fourth week of heat exposure). Water to feed intake ratio was 1.8 to approximately 2.0 during acclimation and recovery, but increased to 3.0 to approximately 3.4 during heat exposure. Internal egg quality parameters were in general unaffected by Tw. The two warmer Tw regimens in Experiment 2 had less reduction in egg size than did the two cooler Tw. In both experiments, hens displayed anticipatory increase in feed and water intake 2 to 3 h prior to lights-off. However, the stimulus of lights-on did not elicit a strong return to feed and water consumption as typically seen in broilers. The results revealed the potential existence of an optimal Tw range (near 23 C) for heat-chal lenged laying hens. Larger-scale tests are warranted to further verify the findings.

Acclimatization↗
PubMed1988

Reproductive performance of hens fed field beans and potential relationships to vicine metabolism.

Field beans (faba beans, broad beans, horse beans, ackerbohnen, Vicia faba L.) depress weight of eggs when fed to laying hens. Vicine isolated from field beans has been shown to depress egg weight and hatchability when fed in large amounts. The present study was undertaken to determine the effect of using three varieties of field beans, varying in tannin and total vicines content, at 20% in breeder diets on reproductive performance of hens and associated vicine transfer from the diet to the egg. Data on egg production, feed consumption, egg weight, body weight, egg quality, hatchability, and hen blood chemistry were obtained. Direct spectrophotometric and high pressure liquid chromatographic (HPLC) analyses of field beans, egg albumen, and egg yolk were conducted. Performance of the hens was excellent on all production characteristics except that there was a nonsignificant reduction in egg weight, a significant reduction in egg shell thickness for hens fed all three types of field beans, and a highly significant reduction in hatchability of eggs from hens fed one but not the other two sources of field beans. The hatchability effect was not correlated with vicine or tannin content of the field beans and only traces of vicine were transferred to the egg by the hen from the diet. Although larger amounts of vicine depressed hatchability when injected into fertile eggs, the trace amounts found in eggs from feeding field beans did not account for the reduction in hatchability observed in this study. It is possible that the hydrolysis product of vicine, divicine or the analogous product from convicine, isouramil, or both, may be involved in toxicity, because these substances are known to be the cause of a hemolytic anemia in some humans that suffer from favism due to consumption of field beans.

Animal Feed↗
PubMed2004

Is there a trade-off between fecundity and egg volume in the parasitic copepod Lernanthropus cynoscicola?

Negative relationships between egg number and egg size are commonly seen in many animal taxa, supporting the idea that there is a trade-off between egg number and egg size resulting from the allocation of resources to either one or the other. In parasites, where availability of resources is presumably very high, there may be fewer energetic constraints acting on allocation strategies, and the trade-off may be weakened. We investigated the association between egg number and egg volume among females of the copepod Lernanthropus cynoscicola Timi and Etchegoin, 1996, parasitic on the fish Cynoscion guatucupa (Cuvier). Both egg number and egg volume were strongly correlated with female body size. After controlling for the effects of body size, we found absolutely no evidence of a trade-off, i.e. no negative relationship, between egg number and egg volume. For a given body length, females that produce many eggs do not tend to produce relatively small eggs, and vice versa. In contrast, under conditions in which resources are plentiful, large females produce large quantities of high-quality eggs, and have a marked fitness advantage over small females.

Animals↗
PubMed1976

Effects of feeding ethyl mercury chloride to chickens.

Four groups, 0, 5, 10 and 20%, of Single Comb White Leghorn chickens (30 males plus 30 females each) were fed a diet which contained either 0, 5, 10 or 20% ethyl mercury chloride dressed wheat for a period of 88 days. The wheat was dressed with the organic mercury compound at the rate of 500 gm. ethyl mercury chloride per metric ton of wheat. Therfore, the diets contained respectively 0, 25, 50 and 100 mg. organic mercury compound/kg. With average daily feed consumption of 101, 102, 101 and 98 gm. by the individual birds of the respective groups, the birds did not show any symptoms of disease during the course of the study. Egg production, egg quality and mortality of the treatment groups were comparable with those of the control group. The amount of residual mercury in egg white and yolk was determined at intervals. The residual mercury of egg white of the treatment groups was about three times as much as that of egg yolk, and made its significant appearance in the 20% group on the third day of the trial. The concentration was increasing with time in both white and yolk and was parallel to the concentration of the organic mercury in the diet. The liver followed by the kidney of both sexes accumulated the highest amounts of mercury. Tissues of female birds accumulated less mercury than tissues of male birds did probably due to the passage of some of the ingested mercury with the egg white and yolk. The results were discussed on the basis that the kind of mercury compound, daily intake and duration of treatment play major roles in the determination of induced effects.

Administration, Oral↗
PubMed1989

Bacterial Colonization of Cod (Gadus morhua L.) and Halibut (Hippoglossus hippoglossus) Eggs in Marine Aquaculture.

Aquaculture has brought about increased interest in mass production of marine fish larvae. Problems such as poor egg quality and mass mortality of fish larvae have been prevalent. The intensive incubation techniques that often result in bacterial overgrowth on fish eggs could affect the commensal relationship between the indigenous microflora and opportunistic pathogens and subsequently hamper egg development, hatching, larval health, and ongrowth. Little information about the adherent microflora on fish eggs is available, and the present study was undertaken to describe the microbial ecology during egg development and hatching of two fish species of potential commercial importance in marine aquaculture. Attachment and development of the bacterial flora on cod (Gadus morhua L.) eggs from fertilization until hatching was studied by scanning electron microscopy. The adherent microflora on cod (G. morhua L.) and halibut (Hippoglossus hippoglossus) eggs during incubation was characterized and grouped by cluster analysis. Marked bacterial growth could be demonstrated 2 h after fertilization, and at hatching eggs were heavily overgrown. Members of the genera Pseudomonas, Alteromonas, Aeromonas, and Flavobacterium were found to dominate on the surface of both cod and halibut eggs. The filamentous bacterium Leucothrix mucor was found on eggs from both species. While growth of L. mucor on halibut eggs was sparse, cod eggs with a hairy appearance due to overgrowth by this bacterium close to hatching were frequently observed. Vibrio fischeri could be detected on cod eggs only, and pathogenic vibrios were not detected. Members of the genera Moraxella and Alcaligenes were found only on halibut eggs. Caulobacter and Seliberia spp. were observed attached to eggs dissected from cod ovaries under sterile conditions, indicating the presence of these bacteria in ovaries before spawning. Adherent strains did not demonstrate antibiotic resistance above a normal level. Attempts to regulate the egg microflora by incubation of gnotobiotic eggs with defined antibiotic-producing strains did not result in persistent protection against subsequent colonization by the microflora of the incubator.

Journal Article↗
PubMed1996

Dietary prilled fat and layer chicken performance and egg composition.

Prilled and poultry fat were fed at 2% to 58-wk-old hens and at 4% to 2-wk-old hens for 8 wk. Comparisons by dietary fat source were made within age groups for BW, feed consumption, egg production, egg weight, yolk cholesterol, and fatty acid composition, egg quality, plasma cholesterol, dietary fatty acid utilization, dietary ME, and gastrointestinal transit time of feed. Old hens fed prilled fat had lower egg weight, increased egg production, lower plasma high density lipoprotein (HDL) cholesterol (P < 0.08), and reduced energy. Young hens fed prilled fat were lighter in weight and had lower plasma total and low density and very low density lipoprotein cholesterol. Young hens fed prilled fat had a lower utilization of stearic acid (P < 0.07) but a higher utilization of linoleic acid. In both groups, prilled fat increased yolk saturated fatty acids and decreased polyunsaturated fatty acids. Gastrointestinal transit time of feed was increased by 29 to 31 min (P < 0.09) in young hens fed prilled fat.

Aging↗
PubMed1998

Superovulation in vesper mouse Calomys musculinus (Rodentia-Sigmodontinae).

Optimal conditions for pharmacological induction of ovulation of vesper mouse, Calomys musculinus, were analyzed. The best superovulation (a mean of about 21 eggs per female, range 12-45) was induced by the administration of 12 IU of PMSG followed 48 hr later by injection of 15 IU of hCG. Ovulation started about 10 hr after administration of hCG and was completed during the next 4-5 hr. The induction of ovulation was achieved irrespective of the stage of the oestrus cycle at the moment of PMSG administration. The majority of females (105, 82.7%) responded to the treatment with either an ovulatory (53.4%) or superovulatory (49.7%) response. Oocyte recovery and egg quality were clearly influenced by the age of females, 30 days to more than 120 days old. The majority (90.3%) of superovulated eggs was morphologically normal, and only a small proportion of eggs showed morphological abnormalities (7.4%) or were spontaneously activated (2.3%). Superovulated oocytes under these conditions, were able to undergo normal fertilization in vitro. After 6 hr of sperm-egg interaction in vitro, 87.5% of the oocytes had extruded the second polar body and/or developed pronuclei.

Age Factors↗
PubMed2004

Replacement value of hatchery waste meal for fish meal in layer diets.

An experiment was conducted in which hatchery waste meal (HWM) replaced fish meal (protein for protein) in layer diets at 0%, 33%, 66% and 100% levels. Both feed and protein intake were superior on HWM diets. The highest hen-day production of 73.97% was obtained on diet 2 in which 33% of fish meal was replaced with HWM. Egg weight and egg length were also superior on HWM diets. All birds fed on HWM diets had thicker egg shells (0.33 mm) than did those fed on the control diet, fish meal diet (0.32 mm). Results obtained for yolk weight were statistically different (P < 0.05). Highest values for yolk weight (16.91 g) and albumen weight (40.93 g) were recorded for birds fed with diet 4 in which 100% fish meal was replaced with HWM. HWM can replace fish meal completely in layer diets without adverse effect on egg quality characteristics.

Animal Feed↗
PubMed1989

Avidin traps biotin diffusing out of chicken egg yolk.

1. The unequal distribution of biotin and biotin-binding proteins between the yolk and albumen of freshly laid chicken eggs provides the potential for time-dependent redistribution of biotin that could affect egg quality, biotin availability, and hatchability. 2. Avidin-bound biotin was measured in albumen next to the shell and next to the yolk in eggs stored up to 23 days. 3. Biotin bound to biotin-binding proteins (BBP-I and BBP-II) was measured at the center and periphery of yolk from the same eggs. 4. After 11 days of storage, significant amounts of biotin from the yolk began to accumulate in the albumen adjacent to the yolk. 5. This transfer is attributed to a change in the vitelline membrane that permits diffusion of biotin, not BBP-I or BBP-II, out of the yolk. 6. The dynamics of this phenomenon suggest that in addition to its antimicrobial role, avidin may be involved in the utilization of biotin by the chick embryo.

Animals↗