Effects of Sex on Growth Performance, Carcass Traits, Blood Biochemical Parameters, and Meat Quality of XueShan Chickens

The demand for high-quality chilled chicken has continued to increase in China. Chickens are sexually dimorphic, and to better understand the specific differences in chicken production based on sex, we examined how sex affects growth performance, carcass traits, and meat quality of yellow-feathered chickens. Male and female Xueshan chickens were used as the experimental model. Although males exhibited better growth performance, including body weight (BW), body slope, keel, shank length, and shank girth (p < 0.05), as well as carcass traits, such as dressed weight, leg muscle, and lean meat, females had higher carcass and breast muscle yields (p < 0.05). Males had higher follicle density and yellowness (b*) of the skin and better skin than females (p < 0.05). Among blood biochemical parameters, the serum content of corticosterone (CORT) was higher in males, while those of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), total antioxidant capacity (T-AOC), and catalase (CAT) were lower in males than in females (p < 0.05). The pH levels, shear force, and moisture content quality were better in male breast meat, while the intramuscular fat content (IMF) was lower in males than in females (p < 0.05). The redness (a*) and moisture content were higher in male leg meat, while the pH, water-loss rate (WLR), lightness (L*), and IMF were lower (p < 0.05). The muscle fiber diameter and cross-sectional area were also higher in males (p < 0.05). Consumers felt that soup of male chicken was better than female (p < 0.05), while mouthfeel and tenderness acceptance of breast meat were different between the sexes. These results indicate that female chickens can be marketed as a whole carcass, while males are more suitable for processed carcass products. This study provides significant insights into the production and processing methodologies of yellow-feathered chickens.

Effect of rearing systems on immune status, stress parameters, intestinal morphology, and mortality in conventional and local chicken breeds

The majority of poultry meat used to be sourced from intensively housed birds. However, consumer preference has since demanded poultry producers develop more sustainable farming systems. Although free-range farming is considered beneficial for animal welfare, it is not as easy to standardize as an intensive system, which makes the choice of bird genotype appear crucial for alternative systems. In this study, we aimed to evaluate the effect of conventional and free-range rearing systems on the immune status, stress parameters, intestinal morphology and mortality in commercial hybrids (Ross 308) and local poultry strains, Bionda Piemontese (BP), Robusta Maculata (RM), BP x Sasso (BPxS), and RM x Sasso (RMxS). RNA was extracted from the jejunum and spleen to assess the mRNA expression of IL-2, IL-6, IL-10, IL-18, IL-1β, inducible nitric oxide synthase (iNOS), toll-like receptor (TLR)-4, and interferon gamma (IFN-γ). The heterophil:lymphocyte (H/L) ratio and intestinal histomorphometric evaluation were also calculated. We found that compared to the conventional system, the rearing system significantly affected the jejunum expression of IL-10, iNOS, IL-2, and IL-6, where these genes were upregulated in free-range system. A significant interaction between the rearing system and the genotype was also shown. More specifically, local breeds showed a significantly higher expression (P < 0.001) of IL-6 in the free-range system compared to the same genotypes in the conventional system. Moreover, IL-6 is constantly upregulated in local breeds within the free-range system compared to Ross hybrids. We also found significantly increased H/L and mortality rates in the latter, compared to the local breeds in the free-range reared system. The jejunum morphology also demonstrated a significantly higher villus height in BP and BPxS compared to the Ross hybrids. Overall, the results of our study confirm that the intense selection for growth in broiler chickens may have reduced their ability to react to the environmental stimuli related to free-range systems, resulting in a lower adaptability to a free-range environment, thus making them inappropriate for any farming system other than the conventional one. On the contrary, local chicken breeds are able to adapt and survive in the free-range system of rearing, and represent a genetic resource especially when adaptability to free-range conditions is required.

Growth Performance, Carcass Characteristics and Meat Quality of Organically Reared Broiler Chickens Depending on Sex

Simple Summary

Consumers are increasingly interested in the health and nutritional aspects of meat products, with the result that they are willing to pay more for meat products that have been produced naturally, taking into account high standards and animal welfare. Therefore, we decided to examine in a slightly wider perspective the muscles of Ross 308 chickens kept in an ecological system, taking into consideration an additional factor, i.e., sex. As sexual dimorphism is considered to be a factor in meat quality, we decided to examine this factor in our study. At the same time, we investigated the suitability of these fast-feathering broilers for ecological production. The aim of the study was to investigate the effect of sex on the growth performance, carcass traits, meat quality, fatty acid profile and histological traits of the pectoral muscles in organic Ross 308 broiler chickens. The suitability of these fast-growing broilers for organic production systems was also analyzed. As expected, the study confirmed the influence of sex on the analyzed parameters of the pectoral muscles in chickens reared in the organic system.

Abstract

Given the growing interest of consumers in naturally produced meat, we decided to examine the muscles of Ross 308 broiler chickens kept in an ecological system, with the division into two research groups depending on sex. All the analyses were carried out using the appropriate methods recommended by the AOAC and in accordance with the Polish standards (PN), which are described in detail in the relevant section of the publication. The aim of the experiment was to investigate the effect of sex on the growth performance, carcass traits and meat quality, as well as the fatty acid profile and histological parameters, of the pectoral muscles from organic broiler chickens. A total of 60 one-day-old Ross 308 chickens (half males and half females) were divided into two groups, according to the sex, and reared under organic conditions (Org.) until 82 days of age (ten birds, i.e., five males and five females in each of three pens; replications for experimental groups). Compared with the female group, the male group had a higher final BW and carcass weight (p < 0.05). The males had a better growth and slaughter performance than the females. The meat quality traits and fatty acids content were also affected by sex. The meat from females showed a significantly higher (p < 0.05) protein, dry matter, fiber diameter and shear force and a significantly lower (p < 0.05) fat level than the male group. In this research, the suitability of these fast-growing broilers for natural and organic production systems has been researched with regard to the performance, meat quality and histological characteristics of the muscles.

Overview of Native Chicken Breeds in Italy: Conservation Status and Rearing Systems in Use

Simple Summary

The ongoing loss of domestic animal breeds around the world is occurring at an alarming rate. Thus, the registration and preservation of native breeds is of great importance. The aim of this study, which forms part of a conservation program, was to provide an overview of the conservation statuses of native Italian poultry breeds being reared by local breeders in Italy. The data collected by means of a census questionnaire demonstrate the low population sizes of these breeds in Italy and highlight the need for campaigns aimed at publicizing and promoting the benefits of native breeds with the goal of increasing population sizes. Identifying strategies to facilitate breeders’ access to pure breed birds is also essential, and would require collaborative efforts of university research centers, public entities, and breeders.

Abstract

The most reared species of farm animal around the world is the chicken. However, the intensification of livestock systems has led to a gradual increase in the concentration of a limited number of breeds, resulting in substantial erosion to the genetic pool. The initial step of an ‘animal conservation program’ entails establishing the actual conservation statuses of the breeds concerned in a defined area; in this case, in Italy. To this end, a survey of breeds was performed by means of a census questionnaire divided into two parts. The first part collected information on breeds, breeders, housing facilities, and management aspects, the results of which are presented here. The second part of the questionnaire regarded chicken products and their markets, and these data will be reported in a second paper. The breed status of six chicken breeds was shown to be exceptionally worrying, with total numbers ranging from just 18 to 186 birds. Population sizes exceeding 1000 birds was identified for just four breeds, the maximum being 3400. Some improvements in status were noted in relation to breeds which had been the subject of conservation efforts in the past. The two most common breeds reported are the Bionda Piemontese, a double-purpose breed, and the Livorno egg-laying hen. Collo Nudo Italiano, Millefiori Piemontese, Pollo Trentino, and Tirolese chicken breeds and the Castano Precoce turkey breed were not listed by breeders at all. The most reported turkey breeds are the Bronzato Comune and the Ermellinato di Rovigo. The population sizes of native Italian poultry breeds were shown to be generally poor. Italian poultry farmers and the population at large are largely ignorant about indigenous poultry breeds. Thus, promoting the virtues of Italian breeds would help their conservation by encouraging breeders to rear these birds and consumers to buy their products. The identification of strategies to facilitate access to pure breed birds is essential, and will require the collaboration of university research centers, public entities, and breeders. The results presented in this paper constitute the initial part of a more complex conservation program.

Gastrointestinal microbiomes of broilers and layer hens in alternative production systems

Alternative poultry production systems consisting of free-range or pasture flock raised poultry continues to increase in popularity. Based on the perceived benefits of poultry products generated from these alternative poultry production systems, they have commercial appeal to consumers. Several factors impact the health and well being of birds raised and maintained in these types of production systems. Exposure to foodborne pathogens and potential for colonization in the gastrointestinal tract has to be considered with these types of production systems. The gastrointestinal tract microbial composition and function of birds grown and maintained in alternative poultry operations may differ depending on diets, breed, and age of bird. Dietary variety and foraging behavior are potential influential factors on bird nutrition. The gastrointestinal tract microbiomes of birds raised under alternative poultry production systems are now being characterized with next-generation sequencing to identify individual microbial members and assess the impact of different factors on the diversity of microbial populations. In this review, the gastrointestinal tract microbiota contributions to free-range or pasture-raised broiler and egg layer production systems, subsequent applications, and potential future directions will be discussed.