The effect of age and castration on the growth rate, blood lipid profile, liver histology and feed conversion in Green-legged Partridge cockerels and capons

Multi-omics reveal the effects and regulatory mechanism of dietary echinocystic acid supplementation on abdominal fat and liver steatosis in broiler chickens

The accumulation of abdominal fat and the metabolic dysfunction-associated fatty liver disease (MAFLD) are prevalent problems in the poultry industry, and seriously compromise broiler health and reduce economic benefits. Echinocystic acid (EA), a natural product with anti-inflammatory and antioxidant effects, has been demonstrated to reduce abdominal fat deposition and improve intestinal inflammation in mice. However, it has not been reported in poultry research. In this study, we employed chicken hepatocytes (Leghorn male hepatoma cells, LMHs) to construct an oleic acid and palmitic acid (OA/PA)-induced MAFLD model in vitro and 60 male K90 chickens were induced MAFLD by a high-fat diet (HFD) to examine the impact of EA on liver-lipid metabolism and abdominal fat deposition. Moreover, metabolomic analysis, 16S rDNA gene sequencing, and transcriptomic profiling were performed to determine the mechanism of EA. The results showed that EA (10 μM) significantly reduced triglyceride (TG) and total cholesterol (TC) levels in vitro. Moreover, EA reduced abdominal fat deposition without affecting growth performance. EA significantly decreased TC, TG, and low-density lipoprotein-cholesterol (LDL-C) levels, and increased high-density lipoprotein-cholesterol (HDL-C) levels in the blood. Additionally, EA supplementation altered the composition of the intestinal microbiota, particularly by decreasing the ratio of Firmicutes to Bacteroidetes. Furthermore, liver metabolomics analysis revealed that EA increased the abundance of metabolites related to arginine metabolism and mitochondrial oxidation pathways, and these metabolites were predicted to be positively correlated with the gut genera enriched by EA. EA also altered the expression patterns of genes related to liver lipid metabolism and inflammation, particularly CYP7A1, CYP7B1, CYP3A5, and ACAT, which are enriched in the PPAR signaling pathway and steroid hormone metabolism. Moreover, correlation analysis revealed that there was a close correlation between differential gut microbiota, metabolites, and gene expression profiles. Collectively, the results indicated that EA may alleviate MAFLD by regulating steroid hormone metabolism and modulating the gut microbiota. EA may be a candidate feed additive to prevent abdominal fat deposition and MAFLD in the broiler industry.

Effects of caponization and age on the histology, lipid localization and fibre diameter in muscles of Rhode Island Red cockerels

Poultry scientists are constantly studying different breeds of cockerels that would be suitable for capon meat production. Capon meat, although not yet very popular, is characterized by exceptional taste qualities that could appeal to many customers. Obtaining the appropriate palatability, structure and tenderness of capon meat is possible thanks to the reduction in androgen levels following the castration of roosters. Surgical or chemical castration affects the metabolism of fats, thus increasing their accumulation in the abdominal cavity, subcutaneous tissue and muscles. The main aim of our research was histological evaluation and analysis of the concentration and distribution of adipose tissue in muscles in Rhode Island Red cockerels and capons. In addition, we analysed the diameter of the pectoral muscle fibre. The experiment was performed on 200 Rhode Island Red cockerels; the testes were removed at 8 weeks of age. At 12, 16, 20, 24 and 28 weeks of age, 6 cockerels and 6 capons were slaughtered, and samples from the pectoral and thigh muscles were evaluated. Differences in the accumulation of adipose tissue with muscular atrophy (p<0.05) were observed in thigh muscles, with higher amounts in capons than in cockerels. All examined locations in the pectoral and thigh muscles of capons (around the blood vessels, in the perimysium, in the endomysium, and in the sarcoplasm) showed much higher concentrations of lipids compared to the levels in cockerels. The diameters of the pectoral muscle fibres were different (p<0.05) at 12 and 16 weeks of age, and the diameters of the giant fibres were different (p<0.05) at 12 and 20 weeks of age, with higher values in cockerels. The high concentration of lipids in the skeletal muscles of Rhode Island Red capons is impressive. These dual-purpose cockerel breeds can be a source of high-quality meat.

Physicochemical characteristics of meat from capons derived from the crossing of conserved breed hens and meat roosters

The study aimed to determine the effect of castration on physicochemical properties of meat from capons derived from the crossing of Rhode Island Red (R-11) hens and meat roosters. Subjects were 100 crossbred cockerels, which were randomly assigned to 2 groups of 50 each. Group I (control) consisted of intact cockerels and birds from group II were subjected to castration. The castration was performed at 7 wk of age under local anesthesia by a veterinarian. All birds were fed ad libitum with the same feed mixtures and placed on litter under optimal environmental conditions at a stocking density of 5 birds/m². At the end of fattening (20 wk of age), 10 birds whose body weight was similar to group average, were selected from each group for slaughter. After slaughter, the birds were analyzed for dressing percentage and physicochemical parameters of breast and leg muscles, which were subjected to sensory evaluation. The results demonstrated that compared to intact cockerels, capons were characterized by significantly higher body weight, dressing percentage and carcass muscle content. Both the breast and leg muscles of the capons showed better physicochemical parameters and higher sensory score. It is therefore concluded that the birds derived from the crossing of Rhode Island Red (R-11) hens and meat roosters are good material for capon production, their meat is a product of distinctly higher quality.

Effects of Caponization on Growth Performance and Carcass Composition of Yangzhou Ganders

Simple Summary

Goose meat is recognized as one of the healthiest foods. Goose capons are specially bred and consumed in several parts of China for their high-quality meat. However, the effects of caponization on goose growth and carcass traits have remained uninvestigated, and its molecular mechanisms remain unclear. In this research, caponization lowered testosterone and increased the total cholesterol and triglyceride concentrations in serum. Caponization increased live weights by promoting food intake and abdominal fat deposition, and improved meat quality by increasing intermuscular fat. Changes in the expression of these genes indicate that caponization increases the live weight mainly by increasing fat deposition rather than muscle growth. These results expand our understanding of the mechanisms of caponization on growth performance and fat deposition in ganders.

Abstract

In this study, we determined the effects of caponization on the growth performance and carcass traits of Yangzhou ganders. Fifty sham operated geese (the control group) and 80 caponized geese (the caponized group) were selected at 150 days of age and reared until 240 days of age. At 210 days of age, 30 geese from the caponized group were selected and fed with testosterone propionate (testosterone group). The results showed that caponization lowered testosterone and increased the total cholesterol and triglyceride concentrations in serum, live weights, average 15 day gains, and feed intake. Abdominal fat and intramuscular fat were significantly higher in the caponized geese than in the control at 240 days. Gene expression analysis showed that caponization promoted abdominal fat deposition and intermuscular fat content by upregulating the expression of adipogenic genes in the liver, adipose tissue, and muscle tissue. The high expression of SOCS3 in the hypothalamus, liver, and muscle of caponized geese suggests that caponization may lead to negative feedback regulation and leptin resistance. Changes in the expression of these genes, along with the downregulation of PAX3 in the breast muscle and MYOG in the leg muscles, indicate that caponization increases the live weight mainly by increasing fat deposition rather than muscle growth. These results expand our understanding of the mechanisms of caponization on growth performance and fat deposition in ganders.

Effects of gonadectomy on clinical-hematological, metabolic and hormone conditions of cockerels

Gonadectomy (caponization) of cockerels is an important way of increasing their productivity, improving the quality and taste properties of the meat, and obtaining dietary products. The objective of the study was the influence of gonadectomy of cockerels on their clinical condition, morphological composition of blood, hemoglobin content and anabolism in the tissues, their productivity and chemical content of the muscles. In the experiment, we used 30 Adler silver cockerels aged 4 weeks, which were divided into two groups: control (intact) and experimental (gonadectomized) according to the analogue principle, with 15 individuals in each. The experiment lasted for 185 days, including the main period of 175 days. We determined that the body temperature of cockerels after gonadectomy increased as early as days one and three. In the blood of gonadectomized cockerels, the number of leukocytes decreased by 36.3%, thrombocytes – by 24.7%, while hemoglobin concentration, numbers of heterophils, eosinophils, basophils, monocytes and lymphocytes did not change compared with the intact individuals. On days 20 and 185 of the experiment, the concentration of testosterone in the blood plasma of gonadectomized cockerels was lower respectively by 57.1% and 53.1%, whereas no differences were found prior to gonadectomy and on the third day of the experiment. We determined increase in uric acid concentration and decrease in the level of ionizing calcium in blood plasma of gonadectomized cockerels compared with intact individuals, while the content of cortisol, glucose, total protein, triglycerides, cholesterol, total calcium and inorganic phosphorus, and also activities of alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase did not change. Live weight of gonadectomized cockerels in the period from 45 to 105 days of the raising did not change, and was higher by 10.4–17.0% from day 115 to 145, and further remained not different from the control. Thoracic muscles of gonadectomized cockerels contained 1.8 times more fat, while the levels of moisture, dry matter, protein and ash in thoracic and thigh muscles did not change. The conducted studies have revealed the effect of gonadectomy of roosters on clinical-hematological parameters, metabolic processes, productivity of birds and chemical composition of muscles and may be used to improve the production of chicken meat with high dietary and taste properties.

Co-Treatment of Purified Annatto Oil (Bixa orellana L.) and Its Granules (Chronic®) Improves the Blood Lipid Profile and Bone Protective Effects of Testosterone in the Orchiectomy-Induced Osteoporosis in Wistar Rats

This study aimed to evaluate and compare the effects of co-treatment with purified annatto oil (PAO) or its granules (GRA, Chronic®) with that of testosterone on the orchiectomy-induced osteoporosis in Wistar rats. After surgery, rats were treated from day 7 until day 45 with testosterone only (TES, 7 mg/kg, IM) or TES + PAO or GRA (200 mg/kg, p.o.). The following parameters were evaluated: food/water intake, weight, HDL, LDL, glucose, triglycerides (TG), total cholesterol (TC), alkaline phosphatase levels, blood phosphorus and calcium contents, femur weight, structure (through scanning electron microscopy), and calcium content (through atomic absorption spectrophotometry). Our results show that orchiectomy could significantly change the blood lipid profile and decrease bone integrity parameters. Testosterone reposition alone could improve some endpoints, including LDL, TC, bone weight, and bone calcium concentration. However, other parameters were not significantly improved. Co-treatment with PAO or GRA improved the blood lipid profile and bone integrity more significantly and improved some endpoints not affected by testosterone reposition alone (such as TG levels and trabeculae sizes). The results suggest that co-treatment with annatto products improved the blood lipid profile and the anti-osteoporosis effects of testosterone. Overall, GRA had better results than PAO.

The Influence of Sex on the Slaughter Parameters and Selected Blood Indices of Greenleg Partridge, Polish Native Breed of Hens

The aim of the study was to assess the influence of sex, including caponization, on selected physiological and productive traits of Greenleg partridge (GP) birds. The study material consisted of 120 GP chicks (40 females and 80 males), divided into 3 equal groups (4 replication in each) and kept in litter system and fed ad libitum. A total of 40 cocks have been surgically castrated. The body weight (BW) of birds were measured biweekly. At the age of 24 weeks 8 birds/group were slaughtered, their carcasses were subjected to simplified dissection. Blood samples were collected and among others biochemical profile of serum was established. The lowest BW, regardless of age, had hens. From 18th week capons had the highest BW and finally it was similar to cocks. Cocks demonstrated, significantly, the highest carcass yield, however, the biggest proportion of breast muscles were stated in capons carcasses. The effect of sex is very clear in case of abdominal fat pad. The highest proportion of it was found in females but the lack of sex hormones in capons also contributed to a higher fat accumulation. The serum profile showed that the sexual maturity of hens increased lipids content (cholesterol, trigliceroles) caused by laying production.

Effects of Caponization on Growth Performance and Meat Physicochemical Properties of Crossbred Chickens

The aim of the study was to determine the effect of caponizing on body weight and physicochemical properties of meat of the capons – hybrids obtained from the crossing of hens of the Yellowleg Partridge (Ż-33) breed with meat roosters. The study covered 80 hybrid roosters, which were randomly assigned to two groups of 40 animals each (8 boxes of 10 birds in each group). Group I (control) consisted of uncastrated roosters while group II included birds, which were castrated at 8 weeks of age under local anaesthesia by a vet. Birds were fed ad libitum with the same standard diets and kept on litter under optimal environmental conditions with a stocking density of 7 animals/ m2. At the end of fattening, i.e. in the 20th week of life, 8 birds with a body weight close to the group average were selected from each group for slaughter. After slaughter, the effectiveness of the procedure was checked (lack of testicles), then the slaughter performance of birds, physicochemical parameters of the pectoral and leg muscles were determined, and sensory evaluation was performed. The procedure of castration of hybrid roosters had a positive effect on body weight, feed conversion ratio and carcass traits. The pectoral and leg muscles of the capons were characterized by better water absorption, tenderness and sensory evaluation compared to roosters. Among the assessed groups of birds there was also a variation in the colouring of whole carcasses and muscles, which were lighter (L*), more yellow (b*) and less red (a*) in caponized birds. In addition, the castration procedure had a positive effect on the total protein content in both the pectoral and leg muscles, which in turn, with a higher raw fat content, were distinguished by a favourable ratio of n-6/n-3 polyunsaturated fatty acids (PUFA). Based on the results, it can be concluded that the hybrids obtained from the crossbreeding of the Yellowleg Partridge (Ż-33) and Ross 308 meat roosters are good choice for capon production. They can complement poultry meat production with a niche product for consumers looking for products of exceptional quality.

Effect of Caponisation on Bone Development in Native Male Chickens

The aim of the study was to determine the effect of caponisation on the morphometric traits and mechanical parameters of tibial and femoral bones in Greenleg Partridge cocks. The experiment involved 200 cocks. At the age of 8 weeks, 100 birds were subjected to surgical castration. At week 24, the birds were slaughtered and tibial and femoral bones were collected from 10 non-caponised cocks and 10 capons. The caponisation surgery had no effect on the weight and length of any of the long bones but resulted in reduction (P≤0.05) of the ash content in both bones and Ca in the femur. It also influenced the geometric structure of the bones, i.e. there was an increase (P≤0.05) in the second moment of inertia in the tibial bone and the cross-sectional area and mean relative wall thickness in the femoral bone of the capons. The three-point bending test revealed a negative effect of caponisation on the mechanical strength of the bone. Values characterising the highest bone material strength, i.e. yielding load (femur), maximum force moment (tibia) and yielding deformation, bending point resistance, and load-to-deformation (both bones), declined in the capons. The investigations demonstrated a negative effect of caponisation on the quality of long bones. The tibial bone seems to be slightly more sensitive to the caponisation effects than the femoral bone. It can be assumed based on the analysis of biomechanical traits that the bones of capons are more susceptible to deformations or fractures due to their modified geometry and mechanical brittleness.

Suitability of layer-type male chicks for capon production

The aim of this study was to determine the effect of age and caponization on the growth performance and carcass quality characteristics of Leghorn cockerels. The experiment was conducted on 224 Leghorn cockerels. At 8 wk of age, 112 birds were surgically castrated by a qualified veterinarian in accordance with Commission Regulation (EC) No. 543/2008. The birds were divided into 2 sex categories (with 8 replications per group and 14 birds per replication). The birds were raised to 28 wk of age, and were fed commercial diets ad libitum. From 12 wk of age, at 4-wk intervals, 8 intact cockerels and 8 capons (1 bird per replication) were selected randomly and slaughtered. Caponization had a beneficial influence on the feed conversion ratio (FCR). FCR (kg/kg) based on body weight (BW) gain, carcass weight gain, and edible weight gain was lower in capons from 24 wk of age (P < 0.05), and FCR based on lean weight gain was lower in capons from 21 wk of age (P < 0.05). The content of edible components expressed as a percentage of the total BW of cockerels and capons was similar in the corresponding age groups. Caponization had no effect on the total lean meat content of the carcass (P = 0.744), but differences were found between the weights of breast muscles and leg muscles. In week 24 and 28, the weight of breast muscles was higher in capons than in cockerels (P < 0.05). Cockerels had higher leg muscle weight than capons, and significant differences were noted in week 16 and in 28 (P < 0.05).

Three-Point Scale of Lipid Concentration and Localization in Muscle Tissue of Birds Using Oil Red O Staining

Research on skeletal muscles includes chemical, sensorial, histopathological, microbiological analysis, and the influence of observed data on meat quality. The aim of this paper was to establish a point scale for analysing the fat concentration in breast and thigh muscles of birds during histological examination. The need for a point scale showing lipid localization arises during the experiment, including the castration of the bird. During necropsy, pectoral and thigh muscles were put into 30% saccharose solution with the addition of sodium azide. Then, frozen samples were cut into 8 µm sections and stained with Oil Red O (Bio-Optica, Milan, Italy) to detect lipids. Four main locations were evaluated: the area around vessels, perimysium between fascicles, endomysium between fascicles, and sarcoplasm of the fibres. Each location was separately evaluated for pectoral and thigh muscles. The percentage of tissue occupied by lipids in different locations was detected using Panoramic Viewer software (3DHISTECH, Budapest, Hungary). The results from the point scale analysis, similar in pectoral and thigh muscles, confirmed data from the chemical analysis. Significant differences were observed in all examined periods in chemical analysis (P<0.05) and were visible in the point scale with a higher number of birds with higher lipid concentration in all examined locations. Our scale analysis of lipid concentration, confirmed by chemical analysis, is an objective tool and can be used separately in muscle tissues in experiments where there is the need for lipid visualization. An established three-point scale can be a tool in poultry muscle tissue evaluation because not only accumulation but also lipid location is crucial in determining the usefulness of meat in culinary processing.

Effects of caponization and age on the histology, lipid localization, and fiber diameter in muscles from Leghorn cockerels

Poultry researchers seek general and native lines of birds for capon production. The primary aim is to find high-quality meat with valuable sensory attributes. Castration decreases androgen levels and changes lipid metabolism, resulting in the accumulation of abdominal, subcutaneous, and intramuscular fat, which changes the flavor, texture, and tenderness of the meat. Histological analysis of selected skeletal muscles from Leghorn capons and cockerels was the main aim of the present study, along with examination of lipid localization in muscle tissue. We also assessed fiber type and diameter in the pectoral muscles (pectoralis major). The experiment was performed on 200 Leghorn cockerels; testes were removed at 8 wk of age. At 12, 16, 20, 24, and 28 wk of age, 6 cockerels and 6 capons were slaughtered, and samples from the pectoral and thigh muscles were evaluated. Differences in the focal necrosis of the fibers with infiltration of lymphoid cells (P < 0.05) were observed in thigh muscles, with higher numbers in cockerels than in capons. All examined locations in the pectoral and thigh muscles of capons (around the blood vessels, in the perimysium, in the endomysium, and in the sarcoplasm) showed higher concentrations of lipids compared to levels in cockerels. The analysis of fiber type in pectoralis major muscles revealed that all fibers were type IIB. The diameters of the fibers of the pectoral muscles were different (P < 0.05) at 28 wk of age, and the diameters of the giant fibers were different (P < 0.05) at 16 wk of age. The high concentration of lipids in the skeletal muscles of Leghorn capons is remarkable. Thus, ethical reasons as well as economic reasons should be considered when one-day-old cockerels are eliminated.

Effects of caponisation and age on the histology of the internal organs of Leghorn cockerels

1. Poultry researchers seek the most efficient bird line to produce capons (castrated cockerels). The previous studies did not include results from histopathological analyses of internal organs after caponisation. No data have been published on whether adipose tissue accumulates in internal organs or if caponisation changes the structure of the lymphoid organs and the accumulation of lymphoid cells. 2. The aim of this study was to analyse the occurrence of histopathological lesions in internal organs from Leghorn (layer-type) capons and cockerels at different times of fattening. 3. Two hundred, one-day-old Leghorn cockerels were used in this experiment. At 8 weeks of age, the birds were randomly divided into a control group (100 uncastrated cockerels) and a second group consisting of 100 castrated birds. At 12, 16, 20, 24 and 28 weeks of age, six cockerels and six capons were slaughtered. Samples of all internal organs from six cockerels and six capons at each slaughter age were evaluated. 4. The main histopathological differences between capons and cockerels were related to the accumulation of adipose tissue, with higher values noted in capons, especially in the gizzard and the caecum submucosa and fatty degeneration in liver hepatocytes. 5. Additionally, differences were observed more often in cockerels than in capons with regard to depletion of lymphoid cells in lymphoid organs, including the thymus and bursa of Fabricius in 28-week-old birds and the spleen in 24-week-old birds. 6. These studies prove that caponisation causes the accumulation of fat in internal organs and changes the structure of lymphoid organs. 7. Age influences the occurrence of desirable lesions, such as the accumulation of adipose tissue within the examined organs, and older capons (24 and 28 weeks old) are better sources of high quality, potentially edible tissues.