Examining the Nutrient Exchange in All Incubation Periods in Chukar Partridges

Background: This study was conducted to examine the development of the embryo during incubation and the composition, amount and consumption of the egg nutrients among Chukars (Alectoris chukar). Methods: A total of 1210 eggs were carefully separated into their components (albumen, yolk, shell, amniotic-allantoic fluid and embryo) on day 0 (fresh), in the first (day 7), second (day 14) and third (day 21) weeks of incubation and on the hatching date. The moisture, crude protein, crude fat, carbohydrate, crude ash and energy level were determined in egg components. Result: The albumen, yolk, shell, fluid and embryo rates were calculated to be 53.62, 34.84, 11.53, 0.0 and 0.0% in fresh egg, 16.74, 33.49, 16.22, 31.76 and 2.06% in the first week of incubation, 15.65, 28.32, 15.58, 23.35 and 17.10% in the second week of incubation and 0.0, 23.33, 19.38, 0.0 and 57.29% in the third week of incubation, respectively. The hatching weight of the chick was 16.16 g. The nutrients of the yolk, albumen, fluid and shell proportionally varied significantly in different periods of incubation. According to the nutrient changes calculated based on the weight differences of egg components, carbohydrates were mostly used for nutrients during incubation. It was found that even though the nutrients in all the egg components were used in the different periods of incubation, egg yolk was an important source for the embryo throughout the incubation period.

Effects of Laying Cycle Periods on Egg Quality, Egg Chemical Composition, and Reproductive Performance of Japanese Quail Breeders Reared in Northern Algeria

Egg quality traits in quail breeders depend on various factors which may influence embryo survival during incubation, affecting the chicks' production and quality. The current study aimed to determine the effect of the laying period on the external and internal quality of the egg, the chemical composition of albumen, yolk, and eggshell as well as the reproductive parameters of quail breeders. A total of 450 quails (Coturnix japonica) obtained from the same hatchery, were reared in a battery cage with a sex ratio of 1 male to 3 females. All the quails were subjected to standard breeding conditions and fed a balanced laying diet. A total of 960 eggs were collected at two different periods of the laying cycle, the beginning period of the laying (BP indicating 10 weeks of quail age) and the peak period of laying (PP showing 20 weeks of quail age). At each laying period, 30 eggs were used to analyze the various parameters of egg quality, and 450 eggs were randomly selected to assess the reproductive performances. Overall, no differences in the external quality of eggs, such as egg length, egg width, and the egg shape index, were recorded between the two laying periods. Apart from albumen weight that tended to be higher at the peak laying period, the shell and the yolk weights were not affected by the period of laying. Additionally, Japanese quail tend to deposit similar proportions of shell, albumen, and yolk at the two periods of laying. Likewise, the rate of dry matter of the three egg components, shell mineral concentrations, and yolk fat concentrations did not show any noticeable variation with the laying period. The most significant effect of the laying period was related to the potential reduction in the total protein content of the albumen and the yolk of eggs laid at the peak period of laying. Finally, the laying period did not significantly affect the fertility and hatchability rate of the incubated quail eggs but slightly improved the embryonic mortality rate during the peak laying phase.

Transferrins Reduce Replication of Chlamydia suis in McCoy Cells

Chlamydia suis (C. suis) resides in the intestines of pigs and tetracycline-resistant strains are emerging worldwide. Intestinal infections are often subclinical. However, the gut is regarded as a C. suis reservoir and clinical infections have been associated with enteritis, conjunctivitis, pneumonia and reproductive failure. C. suis was found in boar semen and venereal transmission occurred. We studied the anti-Chlamydia suis activity of ovotransferrin (ovoTF) and bovine lactoferrin (bLF). Pre-incubation of C. suis with bLF or ovoTF had no significant effect on overall chlamydia replication (mean fluorescence area) in McCoy cells. The addition of ovoTF to the culture medium had no effect on bacterial replication, but the addition of 0.5 or 5 mg/mL of bLF significantly reduced the inclusion size by 17% and 15% respectively. Egg components are used for cryopreservation of boar semen. When inoculating an ovoTF-containing and Chlamydia suis-spiked semen sample in McCoy cells, a significant reduction in inclusion number (by 7%) and overall replication (by 11%) was observed. Thus, we showed that transferrins possess anti-chlamydial activity. Moreover, ovoTF addition to semen extenders might reduce C. suis venereal transmission. Further research is needed to unravel the mechanisms behind the observations and to enhance the effect of transferrins on C. suis.

Effect of contact with male on the physical and chemical qualities of eggs of black harco layers

A group of 30 Black HARCO laying hers were reared together with 3 mature cocks, while another group were reared in an adjacent pen without cocks. Thus, while the first group of hens had full physical contact (including mating) with the males, the second group was restricted only to auditory and visual contacts with the males. Twelve eggs were selected at 2 - weekly interval within a 12 - week period from each group and chemically analyzed for total protein, cholesterol in the yolk were determined by colourimetric methods while the shell calcium concentration was determined by a litrumetric method. Egg yolk cholesterol was higher (P<0.05) in hens exposed to full physical contact with the males (16.78 vs 14.20 mg/ml) whereas egg yolk protein, albumen protein and egg shell calcium concentrations were not significantly different (P>0.05) between the 2 groups. Egg weight, egg components weights and hen day egg production were also lower in those hens exposed to full contact with the males. Physical contacts (including mating) between the cock and hen resulted in higher yolk cholesterol and lower physical qualities of eggs produced under such management system.

Effect of Organic and Inorganic Dietary Selenium Supplementation on Gene Expression in Oviduct Tissues and, Antioxidant Capacity of Laying Hens

Some functional genes were investigated for their involvement in egg (eggshell biomineralization) formation and selenoproteins in the oviduct and liver of laying hens fed different organic and inorganic selenium source. A total of 24 hens were selected randomly from the four treatments and slaughter. Uteri and liver tissue samples were collected from hens during the active growth phase of calcification (15 - 20 h post-ovulation) for RT-PCR. The basal diets supplemented with 0.3mg/kg of different organic Se sources and sodium selenite upregulate uterine and selenoproteins mRNA levels. This research reaps the advantage of tissue sampling from specialized segments of the oviduct that consecutively form different egg components. Expression of OC-17 and OC-116, and OC-17 were significantly higher in the uterus and magnum of laying hens, respectively. Their higher expression was observed with organic Se (bacterial selenoprotein or Se-yeast) fed-hens. The results may postulate the efficacy of organic Se in enhancing the expression of functional genes involved in the egg (eggshell biomineralization) formation and selenoproteins compared to inorganic and non-Se supplemented hens. This study proposed the efficacy of bacterial selenoprotein in the upregulation of the uterine genes and hepatic selenoproteins in laying hens.

Prediction of Japanese quail egg weight using egg components as regressors

This study was conducted on one hundred freshly laid eggs from Japanese quails with the purpose of predicting quail egg weight (EW) from some internal and external egg components, and also to have accurate and reliable models, for the prediction of egg weight without the use of sensitive scale. The following external (egg weight, egg width, egg length, shell thickness) and internal (yolk width, yolk length, albumen height and haugh unit) components were measured and the level of relationships between them were determined. Descriptive statistics for egg weight, egg length, egg width, albumen height, yolk height, yolk width, shell thickness and haugh unit were 9.13g, 2.97cm, 2.33cm, 0.57cm, 1.14cm, 2.18cm, 0.13mm and 57.58, respectively. Intercept and slope of regression between variables were determined. Generated values were used in multiple, double and simple linear regression equations, respectively. A total of ten prediction equations comprising three multiple, six double and nine simple linear resulted from the data generated. All the equations developed can be used in egg type quail operations. Each prediction equation with egg weight as the dependent variable will assist poultry breeders and farmers in particular in determining the precise egg weight of eggs laid by birds on the farm.