Prolactin (PRL), secreted from the anterior pituitary, plays extensive roles in osmoregulation, corpus luteum formation, mammogenesis, lactogenesis, lactopoiesis, and production of crop milk. In birds, prolactin (PRL) is generally accepted as crucial to the onset and maintenance of broodiness. All the actions of prolactin (PRL) hormone are mediated by its receptor (PRLR), which plays an important role in the PRL signal transduction cascade. It has been well established that the PRL gene is closely associated to the onset and maintenance of broody behavior, and could be a genetic marker in breeding against broodiness in chickens. Meanwhile, the prolactin receptor (PRLR) gene is regarded as a candidate genetic marker for reproductive traits. PRLR is also an important regulator gene for cell growth and differentiation. The identified polymorphism of this gene is mainly viewed in terms of egg production traits. Due to different biological activities attributed to PRL and PRLR, they can be used as major candidate genes in molecular animal breeding programs. Characterization of PRL and PRLR genes helps to elucidate their roles in birds and provides insights into the regulatory mechanisms of PRL and PRLR expression conserved in birds and mammals.

The aim of the study was to determine body weight and dimensions, body conformation, length of the esophagus, length of intestine and its segments, as well as weight of internal organs and their proportions relative the body weight of broiler chickens from three commercial lines -Ross 308, Hubbard Flex and Hubbard F15. At the age of 42 days, Ross 308 chickens had significantly (p≤0.05) shorter trunk, but greater chest circumference and compactness index, as well as shorter esophagus and longer large intestine compared with Hubbard F15. The longest large and total intestine was found in Ross 308 broilers. Chicken genotype had no significant effect on the percentage of the main internal organs, i.e. liver, heart, proventriculus, gizzard, and spleen. In the analyzed broilers, the coefficients of correlation between body weight and dimensions and the length of the esophagus, small intestine, caeca and large intestine were low and not significant. This study provides information relevant to breeding practice, including that the development of internal organs in broiler chickens raised under intensive conditions has an effect on their meat characteristics.

ObjectiveThe study was aimed to compare carcass traits, physicochemical and textural properties of meat in two different genotypes of Pekin ducks with regard to sex effect.MethodsThe study involved 120 Pekin ducks: 30 males and 30 females of strain P33 (Polish native Pekin ducks) and 30 males and 30 females of Star 53 HY (commercial hybrid Pekin ducks). At 49 d of age, 48 birds (12 males and 12 females of each genotype) were selected for dissection. After the dissection, meat samples were collected to determine meat quality traits.ResultsThe studied Pekin ducks of different genotype showed significant differences in body weight, carcass weight, dressing percentage, as well as percentages of breast muscles, skin with subcutaneous fat, abdominal fat, neck, and remainders of eviscerated carcass with neck. Duck genotype influenced the content of crude protein, crude fat, Na, K, P, Zn, pH24, electric conductivity (EC24), cooking loss, L*, a*, most textural traits of breast muscle, and also Na, Mg and Fe content, EC24, drip loss, cooking loss and L*, a*, and b* colour coordinates of leg muscles. Regardless of genetic origin, males exhibited higher BW, carcass weight and carcass neck percentage, as well as lower redness, hardness, chewiness and gumminess of breast muscle compared to females. The genotype×sex interaction was significant for the crude fat content and cooking loss of breast muscle, and for the yellowness of leg muscle.ConclusionStar 53 HY ducks are more suited for broiler production due to their higher body weight and dressing percentage. Their breast and leg meat are characterized by more beneficial chemical composition but has poorer sensory and textural properties compared to the meat of P33 ducks.

Three commercial lines of broiler chickens, Ross 308, Hubbard Flex and Hubbard F15 were investigated. Preslaughter weight, weight of eviscerated carcass with neck and dressing percentage were the highest in Hubbard Flex and the lowest in Ross 308 chickens. Analysis of carcass composition showed statistically significant differences in the content of neck, wings, breast muscles, skin with subcutaneous fat, abdominal fat and remainders of the carcass. The highest muscle content (total proportion of breast and leg muscles in carcass) was found in Hubbard Flex chickens, and the lowest body fat content (total proportion of skin with subcutaneous fat and abdominal fat) in Ross 308 birds. Chicken origin had a significant effect on pH 15 , water holding capacity, colour lightness (L*), yellowness (b*) and aroma and juiciness of breast muscles.Keywords: broiler, meat colour, sensory properties, tissue composition DETAILED ABSTRACT Badania przeprowadzono na kurczętach brojlerach z linii komercyjnych: Ross 308, Hubbard Flex, Hubbard F15. Największą masę ciała przed ubojem, masę tuszki patroszonej z szyją i wydajność rzeźną miały kurczęta Hubbard Flex, a najmniejsze Ross 308. Analiza składu tuszek wykazała statystyczne istotne zróżnicowanie pod względem zawartości szyi, skrzydeł, mięśni piersiowych, skóry z tłuszczem podskórnym, tłuszczu sadełkowego i pozostałości tuszki. Największe umięśnienie (udział mięśni piersiowych i nóg) stwierdzono u kurcząt Hubbard Flex, a najmniejsze otłuszczenie (łączny udział skóry z tłuszczem podskórnym i tłuszczu sadełkowego) u ptaków Ross 308. Pochodzenie kurcząt wpłynęło istotnie na wartości pH 15 , wodochłonność, jasność barwy (L*), wysycenie barwy żółtej (b*) oraz zapach i soczystość mięśni piersiowych. , p.303-315 303 Journal of Central European Agriculture, 2013, 14(2), p.303-315 DOI: 10.5513/JCEA01/14.2.1263 781 Journal of Central European Agriculture, 2013, 14(2), p.781-793 DOI: 10.5513/JCEA01/14.2.1263 2 DETAILED ABSTRACTCelem pracy było porównanie masy ciała, wydajności rzeźnej, składu tuszki, właściwości fizykochemicznych i sensorycznych mięsa kurcząt brojlerów z trzech linii komercyjnych -Ross 308, Hubbard Flex, Hubbard F15 -utrzymywanych w warunkach produkcji wielkotowarowej. Kurczęta utrzymywano w typowych warunkach produkcyjnych, w budynkach zamkniętych o regulowanych parametrach środowiska, na ściółce. Ptaki żywiono ad libitum przemysłowymi pełnoporcjowymi mieszankami paszowymi dla kurcząt brojlerów. Po 6. tygodniach odchowu z każdej grupy (linii) wybrano losowo po 20 osobników, do dysekcji. Po uboju, odpierzeniu i wypatroszeniu, oznaczono pH mięśni piersiowych i nóg, a następnie wykonano rozbiór (dysekcję) całych tuszek. Z każdej tuszki wyodrębniono: mięśnie piersiowe, mięśnie ud i podudzi (nóg), skrzydła ze skórą, szyję bez skóry, skórę z szyi, skórę z tłuszczem podskórnym, tłuszcz sadełkowy i pozostałości tuszki. Ponadto w trakcie patroszenia wyodrębniono serce, wątrobę, żołądek mięśniowy -jadalne podroby. Poszczególne elementy tuszki i podroby zważono, następnie obl...

The effects of age and sex of guinea fowl on their dressing percentage, carcass composition, pH value, water holding capacity, colour and sensory properties of meat was determined. At 16 weeks of age, males and females had significantly higher body weights and carcass weights compared to birds at 13 weeks of age. The carcasses of older birds contained more breast muscles, leg muscles and skin with subcutaneous fat, and less wings, with a significant difference for males. At both evaluation times, males compared to females had lower body weight, carcass weight, dressing percentage, content of breast muscles and abdominal fat, and a higher proportion of leg muscles. Older birds had significantly lower redness (a*) values for breast muscles in males and for leg muscles in females.KEYWORDS: guinea fowl, slaughter value, colour of meat, sensory property STRESZCZENIE Określono wpływ wieku i płci perlic na ich wydajność rzeźną i skład tuszki oraz wartość pH, wodochłonność, barwę i właściwości sensoryczne mięsa. Samce i samice w wieku 16 tygodni miały istotnie większą masę ciała i masę tuszki niż ptaki w wieku 13 tygodni. Tuszki starszych ptaków zawierały więcej mięśni piersiowych i nóg oraz skóry z tłuszczem podskórnym, a mniej skrzydeł, u samców istotnie. Samce, w porównaniu z samicami miały mniejszą masę ciała, masę tuszki, wydajność rzeźną, zawartość mięśni piersiowych i tłuszczu sadełkowego, a większy udział mięśni nóg. U starszych ptaków stwierdzono statystycznie istotnie mniejsze wartości a* mięśni piersiowych u samców, a w przypadku mięśni nóg u samic.SŁOWA KLUCZOWE: perlica, wartość rzeźna, barwa mięsa, właściwości sensoryczne DETAILED ABSTRACTOcenie podano 60 perlic perłowoszarych. Ptaki utrzymywano na głębokiej ściółce w budynku zamkniętym o regulowanych parametrach środowiska, bez dostępu do wybiegu. W pierwszych czterech tygodniach stosowano promienniki podczerwieni. Odpowiednią wymianę i ruch powietrza umożliwiła wentylacja mechaniczna. W pomieszczeniu z perlicami stosowano światło żarowe. Ptaki utrzymywano w dwóch kojcach, każdy o powierzchni 12 m 2 , po 30 sztuk w jednym kojcu. Perlice karmiono ad libitum przemysłowymi mieszankami dla indyków. Do 3. tygodnia życia włącznie ptakom podawano mieszankę paszową zawierającą 24,5% białka ogólnego i 12,15 MJ (2900 kcal) energii metabolicznej, od 4. do 8. tygodnia mieszankę zawierającą 22,6% białka i 12,35 (2950 kcal) EM, a od 9. tygodnia do końca badań mieszankę z udziałem 20,7% białka i 12,55 MJ (3000 kcal) EM. W 13. i 16. tygodniu wychowu wybrano po 10 perlic do uboju. Po uboju oznaczono pH 15 mięśni, wykonano rozbiór tuszki, pobrano próby mięśni piersiowych i nóg do oznaczeń właściwości fizykochemicznych i sensorycznych. Ptaki 16-tygodniowe miały istotnie większą masę ciała i masę tuszki. Obliczona wydajność rzeźna była większa u ptaków młodszych (w wieku 13 tygodni) oraz u samic w porównaniu z samcami. Wraz z wiekiem stwierdzono zwiększenie zawartości (%) mięśni piersiowych, mięśni nóg i skóry z tłuszczem podskórnym, a zmniejszenie udziału skrzydeł ...

Mongolian × Versicolor and common pheasants were investigated. Birds were kept in a confined, environmentally controlled facility without outdoor access and fed ad libitum commercial diets for slaughter pheasants. Body weight was determined at the end of 6, 10 and 13 weeks of rearing, and body weight and body measurements were determined in 16-week-old pheasants. At 16 weeks, 20 pheasants were taken from each genetic group for slaughter. After slaughter, pH₁₅ of muscles was determined and carcasses were dissected. Samples of breast and leg muscles were collected to determine water holding capacity, colour, and sensory properties of meat. Compared to common pheasants, Mongolian × Versicolor hybrids were characterized by similar body weight and body measurements except for length of trunk with neck in females. The carcasses of Mongolian × Versicolor pheasants of both sexes contained more breast muscles, leg muscles, skin with subcutaneous fat and abdominal fat. Differences in the values of these traits were not significant. Significant differences in the composition of carcasses from the groups under comparison were only found for the content of skin with subcutaneous fat and abdominal fat content in females, which were significantly higher (P ≤ 0.05) in Mongolian × Versicolor females. The leg muscles had significantly higher pH₁₅in Mongolian × Versicolor females and significantly lower (P ≤ 0.05) redness (a*) in males. Compared to the common pheasants, the breast muscles of Mongolian × Versicolor pheasants received lower scores for aroma and tenderness and higher scores for taste, whereas leg muscles had higher scores for intensity of aroma and taste, and lower scores for taste and tenderness.    

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The aim of the research was to determine the effect of replacing part of a commercial feed mixture with whole wheat grain on the bodyweight, carcass composition and meat quality of Pekin ducks. A total of 160 1-day-old sexed SM3 Heavy hybrid ducks were used in the study. Two diets were given during the rearing period (36–49 days): (1) a complete commercial diet ad libitum, and (2) restricted amounts of a commercial diet (85%) and whole wheat grain (15%). Each treatment consisted of four replications of 20 birds each. Adding whole wheat grain to the ration resulted in no significant (P > 0.05) changes in bodyweight (3475.8 g), feed conversion ratio (0–49 days, 2.50 kg DM intake/kg liveweight gain) dressing percentage (70.1%) and carcass tissue composition in ducks at 49 days of age. Breast muscle (superficial pectoral muscle) from ducks fed the commercial diet and whole wheat grain was significantly (P < 0.05) lighter in colour (L* = 39.9 vs 38.0) and a deeper yellow colour (b* = 1.7 vs 0.8), as compared with that from birds receiving the complete commercial diet alone. Breast muscle (superficial pectoral muscle and profound pectoral muscle) also had significantly (P < 0.05) higher threonine (3.9 vs 5.1 g/100 g DM) and valine content (4.0 vs 5.0 g/100 g DM). However, leg muscle (thigh and drumstick muscles) from experimental ducks had a significantly (P < 0.05) lower content of crude fat (5.1% vs 4.2%) and collagen (1.5% vs. 1.1%), as well as less glutamic acid (14.2 vs 12.5), proline (3.5 vs 3.2), alanine (3.0 vs 2.5) and arginine (6.5 vs 5.6 g/100 g DM), as compared with the control birds.