Rearing System Research Articles

Extensive Rearing Systems in Poultry Production: The Right Chicken for the Right Farming System. A Review of Twenty Years of Scientific Research in Perugia University, Italy.

Simple SummaryThe aim of this review paper was to retrace the research journey of the researchers of the Department of Agricultural, Food, and Environmental Science at the University of Perugia, Italy that lasted twenty years and draw updated guidelines regarding the best synergy between chicken type and environment in extensive rearing systems in order to optimize animal welfare, quality, and environmental impact, linked with economical sustainability.The demand for poultry meat, being cheaper than red meat, will drive worldwide production of this product. Accordingly, an increase in production up to 16% is expected in 2025, most of which will occur in developing countries. Most poultry meat production is realized with intensive production systems, and extensive rearing systems (ERS) of poultry (organic, free-range, and low-input) represent only a small portion of poultry production in the EU (about 5%). However, there is an increasing interest in such rearing systems to maintain the good image of product and environmental sustainability, improved animal welfare, and meat quality with an annual trend of growth of about 10%. The aims of this work were to summarize the activities and the viewpoint of the researchers of the Department of Agricultural, Food, and Environmental Science of the University of Perugia (Italy). One of the most important goals of the research unit was the challenge of identifying the best poultry genotypes for ERS, which are important not only for the food industry but also for the improvement of human nutrition. Only the definition of the best genotypes adapted to ERS through the measurement of a wide panel of traits—genetic, physiologic, and behavior—and not only relying on daily weight gain will allow us to achieve this goal.

Kid Growth Comparison between Murciano-Granadina and Crossbred Murciano-Granadina×Boer in a Mixed Rearing System.

Simple SummaryUsually, goat dairy farms have a major problem with the kids they produce for sale, due to their low average daily gain, high feed conversion ratio and poor body conformation, which leads to poor profitability. This paper proposes a solution by crossing the dams not used for replacement with males of a meat breed in a mixed rearing system. The results show that crossbred kids (Murciano-Granadina×Boer) reached the minimum slaughter weight a week earlier than Murciano-Granadina purebred kids, and that there is a decrease of energy content in milk and in the consumption by the kids as their age increases, which shows the importance of having a concentrated feed that complements their needs to express all the genetic potential for growth observed in the references, especially in the crossing of these two breeds. In addition to this, farms that follow this strategy will also be able to improve their profitability through a higher quantity of milk sold.In dairy goats, the low average daily gain and the high conversion ratio for milk and concentrate of the kids mean that their sale price does not offset the costs generated. The hypothesis proposes that a crossbreeding of the Murciano-Granadina breed (MG) with the Boer breed (MG×Boer) will improve the profitability of the kids sold. Thus, the effect of two different groups of kids (purebred MG and crossbred MG×Boer) on birth weight (BW), mortality, average daily gain (ADG), the time for minimum slaughter weight (7 kg) and its variation factors were studied. MG×Boer kids had a 27% greater BW than purebred MG kids (2885 ± 84 g and 2275 ± 74 g, respectively), similar ADG (156 ± 6 g and 142 ± 6 g, respectively) and mortality (18% and 20%, respectively), and reached minimum slaughter weight a week sooner. ADG was less and less as the lactation period progressed due to a lower milk consumption and milk energy value, which highlights the importance of providing a concentrate that will compensate for this reduced energy content. In conclusion, the results show that MG×Boer crossbred kids reached the minimum slaughter weight a week earlier than purebred MG kids, and highlighted the improvement of farm profitability through the increase of milk sold and the need to provide a concentrate feed to enhance the growth of the kids.

Effect of Breed Purity and Rearing Systems on the Stability of Sliced Iberian Dry-Cured Ham Stored in Modified Atmosphere and Vacuum Packaging.

The long-term storage stability of three quality categories of sliced Iberian dry-cured ham defined by the Spanish Iberian Quality Standard (Black, purebred Iberian reared outdoors in Montanera system; Red, Iberian × Duroc crossed (50%) pigs reared outdoors in Montanera system; and White, Iberian × Duroc crossed (50%) pigs commercially fed) and packaged under vacuum and modified atmosphere packaging (MAP) was studied. Commercial category affected the shelf life, being Black and Red presented the highest lipid oxidation during storage, whereas the effect of packaging was not as clear as the effect of commercial category. MAP preserved more the colour and the antioxidants content than vacuum packaging, while this latter reduced lipid oxidation development and maintained better the brightness and flavour of slices than MAP.

Rearing system influences the testicular development, semen quality and spermatogenic cell apoptosis of layer roosters

The objective of this study was to compare the testicular development, semen quality, and spermatogenic cell apoptosis of roosters reared in colony, single, and large cages. Rohman parental layers (n = 540) were randomly allocated into cages of rearing system groups (135 males and 405 females). The experimental period was 70 to 210 d of age. We compared testicular development and plasma main reproductive hormones (Follicle-stimulating hormone; Luteinizing hormone; Testosterone; Estrogen2;) from d 70 to 210 of roosters among the three systems. In addition, routine semen quality indexes, apoptosis of testicular spermatogenic cells and sperm apoptosis of breeding roosters under three rearing systems on d 175 and d 210 were evaluated. Roosters during the growing period (from d 70 to 140) have rapid testis growth and increasing main reproductive hormones in plasma. At the peak of sexual maturity (d 210), in colony cage, the females have a positive effect and promote the testis development of males. However, the stocking density in colony cage has no effect on testicular development; compared with the single and large cage. Roosters reared in the natural mating system had better semen quality, particularly in semen volume, density, and viability; the hatching % of fertilized eggs and healthy chicks were higher for the colony than single and large cages. Furthermore, the sperm density was higher for colony than single and large cages, which was related to the apoptosis of spermatogonia and spermatocyte, not the apoptosis of mature sperm. This study provided the basic data for the reproductive performance research of chicken reared in the colony cages.

Rearing system effects on live weight gain of large white turkeys

The aim of this study was to determine the effect of three production systems on live weight gain (LWG) of white turkeys by repeated measures analysis of variance (ANOVA) and profile analysis. A total of 81 turkey poults were assigned to intensive (7 male and 19 female), semi-intensive (9 male and 19 female) and extensive groups (11 male and 16 female) at one day old. The poults were wing-banded at day 1 after hatching and weighed individually each week through 16 weeks old. The birds were managed similarly through eight weeks old. After that time, the intensive group was fed concentrated feed indoors. The birds of the semi-intensive group had access to pasture for eight hours a day, and received 50% of the concentrated feed that was consumed by the intensive group. The birds in the extensive group were kept outdoors with shade and grazed on pasture, but did not receive concentrated feed. The bi-weekly LWG of the extensive, intensive and semi-intensive groups were 1191.4 g, 990.6 g and 872.1 g, respectively. Through the 16 weeks of the trial, the effects on LWG of production system, age, and interaction of age and production system were highly significant (P <0.01) in the repeated measures ANOVA. The profile analysis also showed highly significant (P <0.01) production system effects and interaction of production system and age on LWG. Scheffe’s test indicated that the intensive, semi-intensive, and extensive treatments differed (P <0.05).

Rearing system with nurse cows and risk factors for Cryptosporidium infection in organic dairy calves

Rearing dairy calves with nurse cows has been increasingly adopted by French farmers especially in organic farming and is characterized by a fostering of two to four calves during the first month of life by an unmilked lactating cow. This type of rearing remains poorly documented regarding its impact on calf health, such as cryptosporidiosis. The objectives of our study were to describe practices related to rearing dairy calves with nurse cows and to evaluate the prevalence, intensity and risk factors for Cryptosporidium infection in calf neonates. Between January and September 2019, the rearing practices of calves were described in 20 organic French farms and faeces were sampled once from 611 animals aged between 5 and 21 days. Cryptosporidium oocyst shedding was identified by modified Ziehl-Neelsen technique and scored semi-quantitatively (score 0–4). The risk of excretion (score 0 versus 1–4) was analysed using multivariate logistic regression models.This cow-calf rearing system usually consisted of a first phase with the dam, followed by an optional phase of artificial milk feeding (calves being fed with whole milk of the farm) and a final phase of fostering by a nurse cow. Each nurse was suckled from one to five calves of close age with a fostering age of 8 days on average. The oocyst shedding prevalence was 40.2 % and similar to classically reared calves, but the intensity of shedding and the prevalence of diarrhoea appeared to be lower. The identified six risk factors for oocyst shedding were: born in the last two thirds of the birth order, born between January and July versus August and September, calf with its dam in the barn versus on pasture, having an artificial milk feeding phase versus being with the dam only, and contact between peer calves and notably the presence of an oocyst excretory calf fostered by the same nurse. These results emphasize the role of the environment for the direct and indirect contamination, particularly that related to the accumulation of oocysts from previous or peer calves facilitating the faecal-oral route of transmission. This highlights the crucial role of the premises used intensively during the winter and spring months with higher densities of calves in the barn compared to outdoor situations promoted by this rearing.

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

Simple SummaryThe 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.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.

Body Condition Score (BCS) and Body Weight of Nellore Brown Sheep at Various Reproductive Stages in Different Systems of Rearing

Background: Body Condition Score in sheep was used to evaluate the adequacy of previous feed supply, decide potential feed requirements in the future, evaluate individual animal health status, decide animal condition during daily routine, welfare inspection and in meat production systems.Methods: 60 Nellore brown ewes from Livestock Research Station, Mamnoor, Warangal district was randomly allotted to three rearing systems i.e Intensive (G1), Semi-intensive (G2) and Extensive (G3) system of each 20 animals. BCS and Body weight of the sheep was recorded at various reproductive stages i.e. just before breeding of animals, during pregnancy and lactation period to assess the nutritional status and reproductive performance of the sheep.Result: The mean average body weight (Kg) of pregnant ewes in G2 group had no significant (P less than 0.05) difference with G3 group. The average mean body weight (Kg) of ewes in G1 (27.58 ± 0.37kg) group had significant (P less than 0.05) difference with G2 (25.50 ± 0.32kg) group during lactation period of 90 days. The total gain of BCS during pregnancy period in the G1, G2 and G3 groups were 0.63 ± 0.06, 0.53 ± 0.06 and 0.44 ± 0.11, respectively. The overall mean BCS of the ewes 48hrs after lambing was higher in G1 (3.0 ± 0.10) group followed by G2 (2.73 ± 0.10) and G3 (2.38 ± 0.08) group.

Production Performance and Egg Quality of Laying Hens as Influenced by Genotype and Rearing System

The aim of this study was to evaluate the effect of rearing systems and genotypes on production performance and egg quality. Isa Brown and New Hampshire genotypes were used in this study. These two genotypes were housed in floor and organic rearing systems. During the experimental period, which lasted one year (52 weeks), the following production performance parameters were recorded: egg production, daily egg mass, feed consumption, feed conversion efficiency, and mortality. Fifteen eggs per group were collected for analysis at 64 weeks of hen age. These samples were evaluated for external parameters (egg weight and egg shape index), internal parameters (albumen height, Haugh unit, and the proportions of albumen, yolk and shell), eggshell quality parameters (shell thickness, shell deformation and shell breaking strength), and eggs’ chemical composition (dry matter, minerals, protein and lipids). Generally, Isa Brown hens had better production performance than New Hampshire hens. At the same time, organic New Hampshire layers performed better than floor-reared ones. Genotype had a significant effect on all ten egg quality parameters (external, internal and eggshell quality), rearing system independently affected only egg weight, and the interaction of the observed factors significantly influenced seven parameters. Genotype had a significant effect on three of the four chemical composition parameters, while no significant effect of the rearing system was established on the chemical composition of eggs. The rearing system x genotype interaction significantly affected the eggs’ protein content.

Evaluation of stress-related parameters and intramural coronary arteriosclerosis in Lidia bulls and Piemontese oxen

The aim of this study was to evaluate how different rearing systems (intensive or semi-extensive) and sexual hormones could affect stress parameters and the development of stress-related intramural coronary arteriosclerosis in Lidia bulls (n = 18) and Piemontese oxen (n = 17). At slaughter, hearts were sampled and submitted to histological investigations in order to evaluate coronary arteriosclerosis. Blood and hair samples were also collected to measure d-ROMS and 20β-dihydrocortisol levels, respectively. No significant differences were recorded for serum levels of d-ROMS between Piemontese oxen and Lidia bulls. On the contrary, Lidia bulls presented higher levels of hair 20β-dihydrocortisol compared to Piemontese oxen (p = .007). Arteriosclerosis was recorded in both the groups. In Lidia bulls, mild to moderate coronary arteriosclerosis was recorded in all the evaluated regions of the heart (right and left papillary muscle; interventricular septum; right and left ventricle free wall; right and left atrium). In Piemontese oxen, mild to severe coronary arteriosclerosis was observed, especially in the left papillary muscle. These results suggest that both cattle breed experienced stress during their rearing cycle. Further studies are needed to clarify the role of housing system and sexual hormones in the development of these subclinical vascular pathology. Highlights Rearing systems can affect animal welfare. Coronary arteriosclerosis, d-ROMS and hair 20β-dihydrocortisol levels can be affected by stress. Lidia bulls and Piemontese oxen experienced different levels of stress during their rearing cycle.

Comparison of Housing Practices Followed by Goat Farmers Under Stall Fed and Extensive Rearing System in Punjab

Comparison of Housing Practices Followed by Goat Farmers Under Stall Fed and Extensive Rearing System in Punjab

Comparative Study on the Growth Performance of Three Varieties of Guinea Fowl (Pearl, White, Lavender) Under Intensive Rearing System in Hot Humid Climatic Condition

Comparative Study on the Growth Performance of Three Varieties of Guinea Fowl (Pearl, White, Lavender) Under Intensive Rearing System in Hot Humid Climatic Condition

Carcass Traits and Meat Composition of Hansli × CSML bird under Intensive and Semi-intensive Rearing Systems

Carcass Traits and Meat Composition of Hansli × CSML bird under Intensive and Semi-intensive Rearing Systems

Genotype by Environment interactions for egg number and egg weight of five dual-purpose chicken breeds in different zones of Oromia region in Ethiopia

The African Chicken Genetic Gain (ACGG) project (https://africacgg.net/) aims at backyard poultry optimization by commercial dual-purpose breeds introduction into Africa. To measure benefits, genotype by environment interaction (GxE) analysis provides guidance while predicting environmental effects on production traits of breeds. A survey among Ethiopian poultry smallholders showed egg sale being the most important purpose of keeping village chickens in Oromia. Data was available about laying of 894 ACGG chickens in Oromia. Hence current research questions were: 1) Does GxE take place? 2) Which breed performs best regarding laying and in which environment within Oromia? Traits investigated were egg number and egg weight of five breeds (S-RIR, Sasso, Horro, Kuroiler and Koekoek) located in three zones (East Hararge, East and West Shoa) and 5 districts (Adami Tulu, Bako Tibe, Dano, Dugda and Haromaya) in Oromia. Observations were taken as group measure performing weighted analyses. GxE was only present for egg number with magnitude strongest for zone. S-RIR performed best for both traits in both environments, except Kuroiler performing better in East Shoa for egg number and Koekoek for egg weight. This indicates success of crossbreed S-RIR. Sasso and Horro performed worst supported by previous research for Horro but not Sasso. Low precipitation in East Shoa caused bigger distance in egg number predictions, being higher for S-RIR and lower for Horro and Sasso compared to West Shoa. Apart from these final conclusions, social context of breeding and data collection difficulties should not be forgotten. Just like relevance of other performance trait analyses.

Water Quality Assessment and Monitoring of Closed Rearing System of the Sea Cucumber Holothuria scabra

Sea cucumbers are an essential fishery resource. Therefore, effective aquaculture methods should be developed to achieve their optimal production. Sea cucumbers are susceptible to various environmental factors, one of which is water quality. Monitoring water quality based on physical and chemical parameters should be useful to the rearing system in aquaculture. In practical use, farmers usually monitor only temperature, salinity, and pH, neglecting the essential role of chemical parameters. This review focuses on and urges the monitoring of physical and chemical parameters. We explored the water quality parameters that may be crucial to the sea cucumber rearing system, including temperature, salinity, pH, dissolved oxygen, ammonia, turbidity, particulate organic matter, total nitrogen, nitrate, nitrite, ammonium, silicate, and phosphate. Furthermore, this paper presents a practical way to monitor the aquaculture or rearing system of sea cucumbers. It is suggested that temperature and salinity are the crucial physical parameters, while the essential chemical parameters are phosphate, nitrate, and ammonia.

White spot syndrome virus (WSSV) disturbs the intestinal microbiota of shrimp (Penaeus vannamei) reared in biofloc and clear seawater.

White spot syndrome virus (WSSV) is one of the most virulent pathogens afflicting shrimp farming. Understanding its influence on shrimp intestinal microbiota is paramount for the advancement of aquaculture, since gut dysbiosis can negatively impact shrimp development, physiology, and immunological response. Thereupon, the data presented herein assesses the influence of WSSV infection and different rearing systems on the intestinal microbiota of Penaeus vannamei. Our study aimed to describe and correlate the composition of shrimp (Penaeus vannamei) gut microbiota, when reared in biofloc and clear seawater, before and (48 h) after WSSV experimental infection. Shrimp were kept in two different systems (biofloc and clear seawater) and experimentally infected with WSSV. Intestine and water samples were characterized by 16S rRNA gene sequencing, before and after viral infection. We observed (i) WSSV induced higher mortality among shrimp reared in biofloc; (ii) WSSV led to a loss of intestinal microbiota heterogeneity, at the genus level, in shrimp kept in clear seawater; (iii) there was a prevalence of Cetobacterium and Bacillus in the intestine of shrimp from both systems; (iv) WSSV did not cause significant changes in intestinal microbiota diversity or richness; (v) regardless of the type of system and time of infection, intestinal microbiota was dissimilar to that of the surrounding water, despite being influenced by the type of system. Therefore, WSSV infection leads to punctual dysbiotic changes in shrimp microbiota, although the virus is sufficiently virulent to cause high mortalities even in well-managed systems, such as a balanced experimental biofloc system. KEY POINTS: • WSSV infection leads to a perturbed gut microbiota in shrimp. • WSSV infection greater impacts microbiota of shrimp reared in CSW than those in BFT. • WSSV infection caused higher mortality levels in shrimp reared in BFT than in CSW. • Rearing system influences shrimp gut microbiota composition. Graphical abstract.

Seasonal Variations in Growth and Physiological Parameters Along with its Relationship with Various Haemato-Biochemical and Mineral Profiles in Black Bengal Goats in Free Range Rearing System

Determining animal growth and physiological parameters, their inter-relationship and correlation with various haemato-biochemical and mineral profile during summer and winter seasons in present climatic conditions are imperative for defining genetic potential and adaptation of black Bengal breed for higher meat production. The recorded body weight was found positively correlated with (P ≤ 0.01)height, heart girth and, linear length during both summer and winter season, indicating that they can be used to estimate body weight in black Bengal goats of different ages under field conditions where scales are not usually available. The pulse rate was found to be negatively correlated with (P ≤ 0.01)body weight during both the summer and winter season. Total erythrocyte count (TEC) was negatively correlated (P ≤ 0.05)with the weight during summer but positively (P ≤ 0.01) during the winter season.

Meat and Fat Quality of Salem Black Goat meat Reared under Different Rearing Systems

Background: The work was carried out to complementary contribution to the comprehensive study of the recently recognised promising Salem Black goat breed’s meat quality raised under intensive and semi intensive systems at different age for both sexes. Methods: The study was conducted on sixty four, three months old Salem Black goat kids (32 males and 32 females) by allotting randomly as16 kids in each group in a 2 X 2 factorial design. Results: The pH value for meat was significantly (P less than 0.05) higher at 9 months male animals. Meat redness (a*) value increased and the lightness (L*) and yellowness (b*) values significantly (P less than 0.01) decreased with age. The shear force indicates that male had significantly (P less than 0.01) higher value. Meat at 6 months had significantly (P less than 0.01) higher sarcomere length. Hydroxyproline content was significantly (P less than 0.01) higher with lower muscle fibre diameter in intensively reared male kids meat. Acid insoluble ash, ether extract and PUFA contents were significantly (P less than 0.05) increased with age in meat. Intensively reared animals had significantly (P less than 0.05) low level of SFA and high level of PUFA, MUFA and PUFA/SFA ratio than semi-intensively reared animals. The intensively reared animal shows better meat quality, more nutritious than semi intensively reared animal meat.

Effects of different rearing systems on intramuscular fat content, fatty acid composition, and lipid metabolism-related genes expression in breast and thigh muscles of Nonghua ducks.

Rearing system is a critical nongenetic factor influencing meat quality of ducks. In this study, a total of 360 birds were randomly allocated into floor rearing system (FRS) and net rearing system (NRS) to compare their effects on intramuscular fat (IMF) deposition, fatty acid composition, and related gene expression in muscles of Nonghua ducks. Sawdust bedding and stainless mesh bed were equipped in FRS and NRS, respectively. At the eighth week (8w) and 13th week (13w), the breast and thigh muscles of ducks were collected to determine the profiles of lipids composition and the expressions of lipid metabolism–related genes. The IMF content was higher in 13w-FRS than 8w-FRS and 8w-NRS in breast muscle, whereas it was higher in 13w-NRS than other groups in thigh muscle (P < 0.05). C16:1, C20:5(n-3) of muscles were higher in 8w-NRS than 8w-FRS, whereas C18:1(n-9)c, C18:2(n-6)c, Ʃ monounsaturated fatty acid (MUFA), and ƩMUFA/Ʃsaturated fatty acid (SFA) ratio of muscles were higher in 13w-NRS than 8w-FRS and 8w-NRS (P < 0.05). C22:6(n-3), C20:4(n-6) of breast muscle and C20:3(n-6) of thigh muscle were higher in 13w-NRS than 13w-FRS (P < 0.05). Fatty acids variation was studied by principal component analysis, exhibiting extensive positive loadings on principal components. SREBP1, ACADL, and FABP3 were downregulated in breast muscle, whereas PPARα and ELOVL5 were upregulated in thigh muscle of NRS ducks at 13w. Principal components were extensively correlated with lipids composition parameters, and principal components of breast muscle 1 and principal components of thigh muscle 1 were correlated with SREBP1 and PPARα, respectively (P < 0.05). In conclusion, with increasing age, FRS enhanced IMF deposition in breast muscle, and the same promotion in thigh muscle was because of NRS. The variation of fatty acids in muscles was uniform, and the change of single fatty acid was unable to distinguish NRS and FRS. However, as NRS downregulated SREBP1, ACADL and FABP3 in breast muscle and upregulated PPARα and ELOVL5 in thigh muscle, NRS could improve nutrient value and meat quality by increasing ƩMUFA, ƩMUFA/ƩSFA ratio, and important PUFA levels. Therefore, NRS was more recommended than FRS for Nonghua ducks during week 8 to 13 posthatching.

Glycogen and lactate contents, pH and meat quality and gene expression in muscle Longissimus dorsi from iberian pigs under different rearing conditions

Forty-four pure Iberian pigs were reared under four different rearing systems: i. Free range conditions and fed on acorns and pasture (AGFR), ii. Free range conditions with grass availability and fed on concentrate (CGFR), iii. Intensive system and fed on concentrate supplemented with 100 ppm of α-tocopheryl acetate (α-Tac) (CI) and iv. Intensive system and fed on concentrate supplemented with 200 ppm α-Tac (CEI). The aim was to investigate the effect of rearing system on pH values, glycogen content [GLY] and lactate content [LAC], myofibrillar and sarcoplasmic proteins solubility and metabolic rate (R-value) in muscle Longissimus dorsi (L. dorsi) at 45 min and 24 h postmortem. In addition, at 24 h postmortem, water holding capacity (WHC), cook loss (CL), drip loss (DL) and instrumental color were analysed. mRNA expression of genes related to glycogenolysis (glycogen phosphorylase, muscle associated: PYGM) and glucose metabolism, both aerobic (pyruvate dehydrogenase kinase 4: PDK4) and anaerobic pathways (lactate dehydrogenase A: LDHA) were sampled within 45 min postmortem. AGFR muscles at 45 min postmortem had a significantly higher [GLY] than CI (P < 0.05). CEI and CGFR muscle [GLY] did not differ from CI and AGFR, with intermediate values. [LAC], pH, R-value and protein solubility, both at 45 min and 24 h postmortem, did not differ among groups. Rearing system did not affect meat quality parameters, with the exception of redness (CIE a*) that was significantly higher in muscle from AGFR pigs than in those from CEI and CGFR pigs. Meanwhile, PYGM mRNA showed overexpression in AGFR, CGFR and CEI groups compared to CI. No significant differences were found for LDHA and PDK4 genes between batches. Regarding correlations, pH had significant positive correlations with WHC and negative with CL and lightness (CIEL L*). [LAC] correlated positively with CL and CIE L * and negatively with WHC; while the pH did the opposite. The expression of the LDHA gene was negatively correlated with pH and positively with [LAC]. Positive correlations were found between PDK4 gene expression and pH and negative correlations with [LAC].