The Effects of Slaughter Age and Sex on Carcass Traits, Meat Quality, and Leg Bone Characteristics of Farmed Common Pheasants (Phasianus colchicus L.).

The aim of this study was to determine the effects of slaughter age and sex on the carcass characteristics, meat quality parameters, and leg bone dimensions of common pheasants. The study material consisted of 40 common pheasants, including 10 males and 10 females at 12 weeks of age and 10 males and 10 females at 15 weeks of age. The birds were kept on a farm in a semi-intensive system. The slaughter age had significant effects on the eviscerated carcass weight; the percentage of skin with subcutaneous fat; the wings percentage; electrical conductivity (EC24); the work required to cut the samples (cutting work); redness (a*); the intramuscular fat content in the breast meat; and the protein, intramuscular fat, water, and collagen contents in the leg meat. The sex of the pheasants had significant effects on the eviscerated carcass weight; the contents of leg muscles, skin with subcutaneous fat, and wings in the carcasses; and the electrical conductivity, thermal loss, lightness (L*), and redness (a*) of the breast muscles. It also significantly affected the protein and water contents of the pectoral and leg muscles, the intramuscular fat contents of the leg muscles, the texture traits of the pectoralis major muscle, and all femur and tibia bone dimensions. The results indicate a greater influence of sex compared to slaughter age on the pheasant traits studied. We confirmed the occurrence of a clearly marked sexual dimorphism in birds of this species. Both factors (slaughter age and gender) have significant effects on the nutritional and technological value of pheasant meat. The few studies on meat texture and the dimensions of pheasant leg bones indicate a need for continued research in this area in the future.

Development of Chicken Embryos in Double-Yolk Eggs: Fertility, Hatchability, Embryo Malposition and Time of Embryonic Mortality.

Fertility rate and hatchability rate are low for all types of double-yolk (DY) eggs in comparison to single-yolk eggs (SY), but these parameters also depend on the number of developing embryos in the egg. The hatchability rate of double-yolk eggs containing two developing embryos (DY2F) is vastly lower than in the case of double-yolk eggs containing only one embryo (DY1F). The aim of the study was to determine the differences between egg fertility rate, hatchability rate, time of embryonic mortality, and embryo malposition during incubation in three types of eggs from Hy-Line Brown hens: SY, DY1F and DY2F. In addition, the quality of the hatched chicks was assessed using the Pasgar©score. Following a 21-day incubation, chicks were obtained from DY1F and SY eggs. No chicks were obtained from DY2F eggs, although the embryos in these eggs developed up to the late stage of incubation. Early (≤7 d of incubation), middle (8-14 d), and late (≥15 d) embryonic mortality was significantly higher in DY eggs than in SY eggs. The embryonic mortality rate during early incubation was the same for DY1F and DY2F eggs, but middle and late embryonic mortality were significantly higher for DY2F eggs. Based on evaluation of embryo position according to Landauer, only three types of malposition that could potentially lead to embryonic death were noted. There were fewer malpositioned embryos in double-yolk eggs containing one embryo. Quality assessment of chicks (Pasgar©score) showed no differences between chicks hatched from eggs containing one yolk and those hatched from double-yolk eggs with one developing embryo, but chicks from double-yolk eggs were significantly heavier. The results of the research will contribute to a better understanding of the development and mortality of embryos in double-yolk eggs.

Comparison of the quality of cage and organic eggs available in retail and their content of selected macroelements.

BACKGROUND: The chicken egg is a food product with a rich content of nutrients, such as proteins, vitamins, lipids, and minerals with high bioavailability. Furthermore, eggs are easy to prepare and a relatively inexpensive component of the human diet. The aim of this study was to compare the quality of eggs from an organic and a conventional farm and their content of Na and K. METHODS: The research material consisted of eggs from laying hens reared in two different systems - organic (according to standards for organic farming and with access to a chicken run) and cage. Forty eggs from each group were analysed. Egg quality traits were divided into destructive and non-destructive. In addition, potassium (K) and sodium (Na) contents were determined in the whole egg, yolk and albumen. RESULTS: The research results indicated slightly better quality of eggs from organic farming compared to eggs from cages in the case of most physical properties. The data clearly show that the content of sodium and potassium in the albumen, yolk and whole egg was higher in the eggs of chickens raised organically compared to the eggs of chickens reared in cages (P ≤ 0.05). CONCLUSIONS: The research results indicate a slightly better quality of eggs from the organic farm compared to eggs from cages in the case of most physical properties, as well as the content of macro-elements. Eggs in both systems are produced following scientific management practices. There are many myths among consumers regarding the nutritional quality of eggs produced in different systems. This information can be useful for raising awareness among consumers selecting eggs.

The effect of the genetic origin of hens on selected egg traits.

BACKGROUND: Eggs have been considered an important component of the human diet for centuries. There is currently a wide assortment of eggs available to consumers, varying in terms of weight (from S to XL), housing system (0 to 3), diet, packaging, etc. Although the egg’s nutritional value is most important to consumers, their perceptions are unfortunately generally based not on facts, but on popular opinion. Most commercial lines of laying hens used in Poland are of foreign origin. However, some farms use commercial lines from Polish breeding farms. Therefore, research was undertaken to determine selected characteristics of eggs obtained from hens of different origins raised in an intensive system, i.e. industrial production of eggs. METHODS: The research material consisted of eggs from Hy-Line Brown and Messa 43 hens from large-scale production. The eggs were obtained from hens at the ages of 35, 40 and 45 weeks. The analysis included selected external and internal characteristics of eggs laid during the study period. The eggs were evaluated immediately after laying, and the following quality parameters were determined: egg weight, shell weight, shell thickness, white weight, yolk weight, and pH of white and yolk. Chemical analysis of dry matter, total protein, crude fat and crude ash content in the whites and yolks was performed. The cholesterol content and fatty acid profile in the yolk were analysed as well. A statistical analysis of the results was performed. RESULTS: The analyses revealed significant differences in the weight and morphological composition of eggs depending on the genotype of the hens. Compared to eggs obtained from Hy-Line Brown hens, eggs from Messa 43 hens had significantly lower shell thickness, greater weight between 35 and 45 weeks of age,       a larger proportion of shell, and a smaller proportion of albumen. Yolks and whites of eggs from Hy-Line Brown hens contained significantly more dry matter and total protein than those of Messa43 chickens, while the cholesterol content in the yolks of both groups was similar. The fatty acid profile of the egg yolk was similar irrespective of the origin of the hens. CONCLUSIONS: Significant differences in egg weight and the parameters of morphological components of eggs were found between the experimental groups. Genotype did not influence cholesterol content or the fatty acid profile in the yolk.

The effect of selected staining techniques on bull sperm morphometry.

Sperm morphometry has some value as an indicator of reproductive capacity in males. In laboratory practice a variety of slide-staining methods are used during morphological evaluation of semen to predict male fertility. The aim of this study was to determine the effect of staining of semen using four different techniques on the morphometry of the bull sperm cell. The material for the study consisted of semen collected from test bulls of the Black-and-White variety of Holstein-Friesians. The results obtained in the study indicate differences in the dimensions of bull sperm heads when different slide staining techniques were used. The most similar results for sperm head dimensions were obtained in the case of SpermBlue(®) and eosin+gentian violet complex, although statistically significant differences were found between all the staining techniques. Extreme values were noted for the other staining techniques - lowest for the Papanicolaou and highest for silver nitrate, which may indicate more interference in the cell by the reagents used in the staining process. However, silver nitrate staining was best at identifying the structures of the sperm cell. Hence it is difficult to determine which of the staining methods most faithfully reveals the dimensions and shape of the bull sperm.

Frequency of Cytoplasmic Droplets Depends on the Breed and Age of Insemination Boars.

In this study an attempt was made to analyse morphological changes in sperm with particular attention to sperm with a cytoplasmic droplet, taking into account the age and breed of the boar. The material for the study consisted of ejaculates of insemination boars of five breeds. Morphological examination of sperm was carried out in 30 randomly selected boars--6 individuals from each breed. The morphology of 500 spermatozoa was evaluated in each slide. The percentage of sperm with normal morphology in the semen of the boars varied between breeds and was dependent in varying degrees on the age of the boar. The primary defects in sperm occurred more frequently in Duroc and Pietrain boars than in other breeds and were more dependent on the age of the boar. The high percentage of primary defects in the sperm of young Duroc boars was determined by the frequency of sperm cells with a proximal cytoplasmic droplet on the midpiece. A particularly high percentage of sperm cells with secondary defects was noted in the initial stage of the reproductive life of the boars. The high number of sperm cells with secondary defects noted in the semen of the Duroc and Pietrain boars and the changes occurring with age in the frequency of secondary morphological defects were mainly determined by the frequency of sperm cells with a distal protoplasmic droplet in the middle piece and to a lesser degree by that of sperm cells with a pseudodroplet.