Volume 20 (2020): Issue 4 (October 2020)

Biosensors can find application in meat and meat products testing for safety, including microbial and other contaminants, and quality, including meat freshness, beef tenderness and pork quality defects. The available biosensors enable the evaluation of freshness, the classification of tenderness of meat products, the evaluation of the glycolysis extent and the presence of the microbial and other contaminants. Since biosensors depend on receptor types, the expansion of knowledge on metabolic transformations occurring in meat contributes to the development of new potential markers and indicators. Examples include assays for glucose, lactates, hypoxanthines, calpastastins, microbial and other contaminants in meat products, augmenting conventional methods. At the same time, biosensors rely on transducers for detection, requiring achievement in many fields including nanotechnology and optics, among others. Biosensors have potential to become a fundamental tool for monitoring and controlling safety and quality of meat products in the future. Hence the aim of the present paper is to present the current state of knowledge on the application of biosensors in meat.

The aim of this review is to summarize the current state of knowledge of reproductive performance of high-yielding dairy cows fed a diet supplemented with n-3 fatty acids (FA s), and to recommend a feeding schedule that can increase the success rate in reproduction. Dietary supplementation with fat, especially FA, has become an accepted strategy for supporting the fertility of high-yielding dairy cows. The two main categories of FA s, unsaturated fatty acids (UFA s) and saturated fatty acids (SFA s), exert distinct effects on reproductive functions, with UFA having a conclusively beneficial impact. Polyunsaturated fatty acids (PUFAs) are of particular importance on account of their biological properties. Standard feedstuffs (such as soybean) are rich in n-6 FA s, whereas few feedstuffs contain n-3 FA s. Neither the n-3 nor n-6 PUFA s are synthetized by the animal. Several field experiments have indicated that the recommended schedule of n-3 supplementation should last 160–170 days, from the eighth week before calving to 100 or 120 days postpartum. Supplementation of the diet thus covers the period from the late preantral stage of the follicle, the entire development of the antrum, oocyte ovulation, and fertilization, as well as the development of the preattachment embryo and its implantation. The following effects are among the important beneficial results of supplementation with n-3 FA s: a higher number of antral follicles suitable for ovum pick-up (OPU), larger dominant follicles and corresponding CL, better quality oocytes and embryos, and higher implantation rates resulting from improved uterine environment (e.g., reduced synthesis of luteolytic PGF2α). We conclude that dietary supplementation for high-yielding dairy cows with n-3 FA s supports ovarian functions and helps the embryo to survive in the adverse environment of the reproductive tract of the postpartum cow.

The purpose of this article is to overview the history of feeding rabbits with different types of animal fats, and to discuss their effects on rabbit performance and quality of their products. Other aspects of the inclusion of various animal fats in rabbit diets are also described. This article is based on the analysis of relevant scientific literature and presents animal fats fed to rabbits, such as beef tallow, butter, pork lard, poultry fat, fish oil, krill oil, oil extracted from insect larvae, mixtures of various animal fats, and mixtures of animal and vegetable fats. The reported papers describe the effect of fats on growth performance, lactation, rearing performance, meat quality, and health status of rabbits. It is notable that in many cases, various animal fats were often an integral part of numerous diets or were included in control diets. The presented information demonstrates that animal fat can be fed to rabbits at 2–4% of the diet without negative effects on reproductive performance, growth performance and quality of meat obtained. Rabbits were used as model animals in many studies in which fat was added to balance the diets and to increase their energy value, especially when investigating various cardiovascular and obesity-related diseases.

The aim of this review is to discuss the usage of insect fats as an energy source in animal nutrition. Insects are a rich carrier of proteins, fat, and minerals. They are successfully introduced in animal diets (poultry, swine, rabbits, fish, and pets) as a source of many nutrients, including energy and essential fatty acids (FAs). The insects’ fat content and quality are highly affected by the type of substrate provided to the insects during the rearing period. The majority of the studies have shown that insect fats may be used as promising substitutes for conventional energy resources in animal nutrition without adverse effects on growth performance and feed utilization. They can positively affect meat quality by increasing the level of long-chain polyunsaturated FAs but may also positively influence animals by regulating the gut microbiota and stimulating the immune system. In conclusion, insect fat supplementation showed promising results in terms of their application in animal nutrition. However, compared to insect protein application, very few studies have been performed on insect fats. Therefore, because of the fat quality and content of insects, there is a need to extend experimentation regarding their implementation in animals’ diets as a replacement for conventional dietary energy resources.

The search is still on for the molecular processes associated with the development and metabolism of skeletal muscles. Selection conducted in farm animals is focused on high muscle mass because it delivers higher economic profit. The present study aimed to shed light on mRNA degradome signals that could be characteristic for molecular processes associated with an abundance of muscle mass and to identify miRNA regulatory networks controlling these processes in pigs applying next-generation-sequencing (NGS). In the study, over 10,000 degraded transcripts were identified per sample, with the highest abundance for genes encoding mitochondrial proteins (COXs, NDs, CYTB, ATP6 and ATP8). Moreover, only 26% of the miRNA targets were found within this degraded transcript pool, which suggested for miRNAs other molecular mechanism at different level of gene expression than mRNA degradation. On the other hand, a small share of the identified degraded transcripts associated with miRNA regulation suggests a different mechanism of mRNA degradation for identified degraded transcropts. Subsequently, most of the miRNA gene degraded targets, such as ENO3, CKM, CRYAB and ADAM19 encode proteins involved in the muscle mass control. The present study showed an interesting dependence between miRNAs and their targets. Nevertheless, the complete view of the miRNA regulatory network could be a subject of further advanced research, which would employ a miRNA transfection procedure in skeletal muscle cell cultures.

Acrylamide (AA) is a chemical substance with a potentially carcinogenic effect. Its presence in food or animal food arises from its thermal processing. The experiment was conducted to evaluate the effect of AA exposure (3.0 mg/kg. b.w./day) of pregnant dams during the second half of the pregnancy on bone development in offspring. As an model animal, guinea pig was used. While term body weight of newborns was not influenced by maternal AA treatment, shorter bones with reduced bone diaphysis cross-sectional area were observed in experimental group. Numerous negative, offspring sex-dependent effects of maternal AA exposure were observed in femoral epiphysis and metaphysis as well as the articular and growth plate cartilages. These effects resulted from the AA-induced alterations in bone metabolism, as indicated by the changes in the expression of numerous proteins involved in bone development: receptor activator of nuclear factor kappa-Β ligand (RANKL), tissue inhibitor of metalloproteinases 2 (TIMP-2), bone morphogenetic protein 2 (BMP-2), vascular endothelial growth factor (VEGF), and cartilage oligomeric matrix protein (COMP), all of whose expression was measured as well as distribution of immature collagen fibres was determined. Based on the results, it can be concluded that the exposure of pregnant dams to AA negatively affected the structure of compact bone in bone diaphysis, microarchitecture of trabecular bone in metaphysis and epiphysis as well as the structure of the articular and growth plate cartilages in their offspring. The AA-induced bone impairment increased osteoclast differentiation, as observed through the change in the RANKL/OPG ratio, which in turn inhibited osteoblast function by decreasing the expression of other proteins. The data of the present study suggests that maternal AA exposure can result in insufficient bone gain and even bone loss after the birth.

Considerable variation in embryo transfer (ET) catheter types, diverging opinions on their quality and functionality, complications following the insertion of catheters, low efficiency of the application of ET methods in humans, and their widely varying efficiency in animals demonstrate the need to improve ET methods and to look for new types of catheters. Such an opportunity is offered by the introduction of catheters made of new-generation biomaterials. This study was aimed to introduce a new generation of biomaterials into reproductive biotechnology. New-generation materials were compared with materials that have been used for many years, and the functionality of newly produced catheters was compared in vivo. Five types of biomaterials were tested: polycaprolactone (PCL), dibutyryl chitin (DBC), polypropylene (PP), polyethylene (PE) and polylactide (PLA). The study was carried out in two stages. Firstly, the basic utility parameters such as geometric stability, surface structure and catheter resistance were evaluated. Subsequently, the biocompatibility of selected biomaterials in embryo cultures was examined, and the development potential of the obtained blastocysts was evaluated. In the second stage, in vivo with live animals, the biomaterials were tested for biocompatibility and the obtained catheters were examined for their ET functionality. Efficiency with the use of the newly produced catheters was determined, the quality of the blastocysts obtained after embryo culture in the uterus was assessed, and oviducts were subjected to histopathological examination after embryo transfer. Of the tested biomaterials, only polyethylene (PE) showed adequate biological and material properties and proved suitable for production of ET catheters.

This study aimed to expand the knowledge of the interactions between prolactin (PRL) and leptin in the ovine mammary gland during pregnancy and lactation; we examined the mRNA expression of prolactin receptor (PRLR), the long form of the leptin receptor (LRb) and suppressor of cytokine signaling (SOCS)-3 in mammary gland biopsies collected on days 60, 90 and 120 of pregnancy and on days 30, 60 and 90 of lactation (n = 6 for each time point), along with the plasma PRL and leptin concentrations. The PRL concentrations were stable throughout pregnancy and increased during lactation. The plasma leptin concentrations were comparable among nonpregnant, early-pregnant, late-pregnant and lactating ewes, but this metric peaked during mid-pregnancy. Expression of PRLR and SOCS-3 in the mammary gland fluctuated during the transition from pregnancy to lactation, and differences in LRb expression occurred during the late stages of lactation. The LRb transcript abundance was approximately 31 times higher in ewes on day 60 of lactation than in early-lactating ewes. Expression of SOCS-3 mRNA in biopsies gradually decreased over the course of pregnancy and reached a minimum value during late pregnancy. After lambing, the transcript level of SOCS-3 increased and peaked on day 60 of lactation. During pregnancy, the plasma PRL concentration positively correlated with the abundances of PRLR (r = 0.971, P<0.01) and SOCS-3 (r = 0.818, P<0.05). Positive correlations were also observed between the transcript abundances of SOCS-3 and LRb (r = 0.854, P<0.05). The variations observed in the plasma PRL and leptin concentrations and the changes in expression of key leptin and PRL signal transduction pathway components, such as PRLR, LRb and SOCS-3, indicate that the efficacies of both hormone actions are modulated in a multilevel manner throughout pregnancy and lactation. These interactions may regulate the ability of the mammary gland to respond to current energy requirements and challenges, thus affecting milk yield and lactation duration.

The aim of the study was to characterize the interrelationship between decreased ruminal fluid pH during subacute ruminal acidosis (SARA) and concentrations of principal constituents of milk and biochemical indices associated with nitrogen utilizations such as rumen ammonia nitrogen (RAN), blood urea nitrogen (BUN) and milk urea nitrogen (MUN). Ruminal fluid samples were obtained by rumenocentesis from 305 cows representing 13 dairy herds. The cows were divided according to ruminal fluid pH into three groups: low, moderate, and high rumen pH cows. The herds were divided into three groups on the basis of the percentages of cows with an assigned value of ruminal fluid pH: SARA-positive, SARA-risk and SARA-negative. SARA-positive herds were characterized by higher concentrations of RAN (12.6 vs. 6.9 mg/dL), BUN (16.2 vs. 10.1 mg/dL) and MUN (12.4 vs. 9.1 mg/dL) compared to SARA-negative herds. Similarly, low-rumen pH cows had greater concentrations of RAN, BUN and MUN than high-rumen pH cows (11.9 vs. 5.8 mg/ dL, 19.9 vs. 14.1 mg/dL, and 12.3 vs. 9.5 mg/dL, respectively). Moreover, SARA-positive herds and low-rumen pH cows had the highest lactose and the lowest fat concentrations in milk. The study demonstrated that the concentration of milk urea nitrogen could be considered one of the indirect and non-invasive indicators of the occurrence of subacute ruminal acidosis in dairy herds.

Bisphenol A (BPA ) is a substance commonly used in the production of plastics. Previous studies have described that it shows multidirectional harmful effects on the living organism. It is known that BPA causes liver damage, but knowledge about the roles of intrahepatic nerves in these mechanisms is extremely scanty. On the other hand, the exact roles of some neuronal substances in the nervous structures located in the liver still remain unknown. One of such substance, which is allocated a role in the stimulation of cell survival is neuregulin 1 (NRG-1). The aim of the present study was to investigate the distribution of NRG-1-like immunoreactive (NRG-1-LI) nerves in the liver in physiological conditions and under the influence of various doses of BPA using routine double immunofluorescence staining. The results (for the first time) show the presence of NRG-1 in the intrahepatic nerves, and co-localization of NGR-1 with neuronal isoform of nitric oxide synthase (nNOS) and vasoactive intestinal polypeptide (VIP). Moreover, it has been observed that high doses of BPA increase the density of NRG-1-LI intrahepatic nerves and the degree of co-localization of NRG-1 with VIP. These observations suggest that NRG-1 located in intrahepatic nerves may play functions in processes connected with liver damage and/or regeneration under the impact of BPA.

The present study was carried out to evaluate the hematology, serum biochemistry, immune responses and oxidative damage of growing beagles fed a diet supplemented with housefly (Musca domestica) maggot meal (MM). Weanling beagles (initial body weight 2.69 ± 0.17 kg) were fed a control diet (0% MM) or experimental diet (5% MM) for 42 days. The results indicated that the diet supplemented with 5% MM had no significant effects on the hematology and serum biochemistry of growing beagles (P>0.05). Meanwhile, neither the serum concentrations of lysozyme and C-reactive protein nor the serum antibody responses to canine distemper virus and canine parvovirus were influenced by dietary MM supplementation (P>0.05). However, dogs in the experimental group had lower serum levels of malondialdehyde and protein carbonyl than those in the control group (P<0.05). These findings demonstrated that MM could be used as an alternative protein source in growing beagles without any adverse effects on hematology, serum biochemistry and immune responses. Furthermore, dietary MM could alleviate oxidative damage in growing beagles.

The present study aimed to determine the effect of the use of Camelina sativa oil as a dietary ingredient for laying hens on their growth performance, fatty acid profile of yolk lipids, and egg quality parameters. In the experiment, 72 Hy-Line laying hens aged 26 weeks were randomly assigned to three groups with four treatments. Control group (I) was fed the diet containing 4% rapeseed oil (RO group). Experimental groups were fed diets containing 4% camelina oil (CSO group) and 10% camelina cake (group CSC). Feed consumption was measured for each group. The number of laid eggs and their weight were recorded every day. Eggs for the assessment of quality parameters were collected in the last 3 days of the experiment. Egg quality, chemical composition of yolk, and fatty acid profile were determined. Organoleptic evaluation was performed on boiled eggs. The inclusion of C. sativa oil or camelina cake in the laying hen diet did not affect egg weight, albumen quality, or taste and flavor. The experimental groups also showed a tendency toward an increase in the proportion of yolk in the egg (%). Addition of 4% camelina oil or 10% camelina cake to the diet of laying hens reduced monounsaturated fatty acid level in yolk lipids and significantly increased n-3 PUFA content, in particular ALA, EPA, and DHA, compared to the control group.

For several years in Europe, there has been a growing interest in the use of native sources of protein (e.g. lupin seeds) in poultry nutrition. The current study aimed to investigate the effectiveness of a microbial phytase in broiler diets with the addition of different levels of white lupin seeds. A total of 480 one-day-old male broiler chickens (Ross 308) were randomly divided into six dietary treatments (10 replications/8 birds per group). The basal diet contained SBM as the main protein source and experimental treatments were prepared with white lupin meal (WLM) at 3 levels (0, 10, and 20%) and with or without phytase inclusion. The experiment was divided into two feeding periods: from 1 to 14 days (starter) and from 15 to 35 days (grower). Diets with phytase addition were deficient in Ca and non-phytate P. All diets were fed in mash form and offered ad libitum. On day 35 excreta were collected and on day 36, ten chickens from each group were euthanized and blood, tibia, and digesta samples were collected for further analysis. The 20% addition of WLM negatively increased the content of phytic-P. The results showed that feed conversion ratio (FCR) and body weight gain (BWG) were not affected by phytase inclusion but by the WLM level alone. In addition, birds fed the diet with 20% WLM were characterized by having the lowest BWG and the highest FCR of all groups. There were no significant differences in feed intake (FI) among chickens fed control and experimental treatments. Regardless of the white lupin level addition, phytase addition improved (P<0.001) nitrogen-corrected apparent metabolizable energy (AME_N). In conclusion, the addition of phytase positively influenced the performance and availability of minerals (Ca and P) regardless of the level of WLM used. However, with regard to the use of WLM in poultry nutrition, it can be assumed that 10% addition is safe and does not affect performance.

The efficiency of the bacterium Bacillus subtilis and white-rot fungus Phanerochaete chrysosporium on growth performance, blood metabolites, carcass characteristics, meat composition and nutrient digestibility of lambs fed crushed whole palm leaf hay was investigated for 105 d. In Experiment 1 (Growth experiment), twenty-four lambs (29.5 ± 1.25 kg) were divided into four feed-based treatments: (1) concentrate and wheat straw ad libitum (control), (2) palm leaf hay (DPL), (3) palm leaf hay supplemented with 2 g of B. subtilis and P. chrysosporium (DPL2) or (4) palm leaf hay supplemented with 4 g of B. subtilis and P. chrysosporium (DPL4). In Experiment 2 (Digestibility experiment), twelve rams, three from each treatment, were used to study nutrient digestibility using the faecal bag technique. Results of the Experiment 1 showed that the DPL4 showed greater (P=0.049) live-weight gain than the control. The diets containing palm leaf hay showed lower (P=0.001) roughage and total feed intake and higher (P=0.001) feed efficiency than the control. Increased serum total protein, globulin, urea-N, aspartate aminotransferase and alanine aminotransferase (ALT) levels were observed with the DPL4 (P˂0.05). Additionally, diets containing palm leaf hay showed higher ALT levels than the control. The DPL4 increased the hot carcass weight (P=0.006) and dressing percentage (P=0.036), and the diets supplemented with B. subtilis and P. chrysosporium decreased (P˂0.05) the tail fat and all fat levels compared with the DPL treatment. Results of the Experiment 2 showed that nutrient digestibility was lower (P˂0.05) with the DPL and DPL2 than with the control and DPL4. Compared with the control, nutrient digestibility of DPL4 was not affected. It is concluded that replacement of wheat straw with palm leaf hay did not affect the feed utilization or animal performance of the lambs; however, supplementation with B. subtilis and P. chrysosporium at 4 g/lamb daily enhanced the growth performance, and carcass characteristics without any adverse effects on blood metabolites.

Common carp (Cyprinus carpio) is the most farmed freshwater fish worldwide. In recent years, use of natural products in fish diets has become popular in aquaculture, to improve fish health and growth performance. The present study investigated the effects of essential oil from the leaves of Monterey cypress (Cupressus macrocarpa; CMEO) on growth performance and blood parameters in common carp fingerlings. Identification of 96.1% of the CMEO total volatile components was achieved, with the highest contents for terpinen-4-ol and α-pinene, at 22.9% and 47.7%, respectively. After 60 days of feeding of the fingerlings with supplemented diets without CMEO (CMEO 0%) and with CMEO at 0.5%, 0.75% and 1%, the best growth performance was seen for those fish fed with the CMEO 0.5% diet. No significant differences were seen for the haematological parameters and blood cell indices versus CMEO 0%. Serum glucose, triglycerides, cholesterol and glutamic pyruvic transaminase were significantly reduced in the fingerlings fed with the CMEO 0.5% diet versus CMEO 0%. Thus, CMEO oil as a 0.5% dietary supplement can be used to improve the growth performance and health status of the common carp without any adverse effects seen.

In this study, the basal diet was supplemented with ethanolic extract of purslane (Portulaca oleracea L.) and the possible effects on growth performance, anti-oxidative, and immune activities of grass carp were evaluated. Fish with initial weight 1.23 ± 0.11 g were randomly divided into four groups (triplicates) and fed purslane extract at 0% (T0), 0.5% (T1), 1% (T2), and 1.5% (T3) for 56 days. At the end of the feeding trial, the results showed that growth parameters were enhanced in T1 groups compared to the control group (P<0.05). Lipase activity in T1 and T2 groups increased, whereas no significant changes were noticed in cases of amylase and protease activities (P>0.05). Catalase and superoxide dismutase activities were enhanced in all groups fed the supplemented diets in comparison with the control group (P<0.05). However, no significant alteration was noticed in the case of glutathione peroxidase activity following the administration of purslane extract (P>0.05). A significant increase in total immunoglobulin level was noted in the T1 group, but lysozyme activity was higher in T1 and T2 groups compared to the control group (P<0.05). In conclusion, supplementation of grass carp diet with the purslane ethanolic extract, especially at 0.5%, can improve growth performance, lipase activity, the antioxidant enzyme activities as well as the immune response of grass carp fingerlings.

The present study investigated the possible effects of including salt of short chain fatty acid, sodium acetate (SA), on skin mucus immune parameters and immune, antioxidant and growth-related genes expression in common carp. There is little data available about the effective role of SA on immune, antioxidant and growth related genes expression as well as skin mucus immune parameters. The aim of this study was to analyse the effect of SA intake on these factors using common carp (Cyprinus carpio) as model organism. Two hundred and forty healthy common carps (mean weight = 15 ± 0.9 g) were supplied and randomly stocked into 12 fiberglass tanks 200 L (20 fish per tank) assigned to four treatments and triplicates. The study was performed in a completely randomized design. The treatments were feeding carps with experimental diets containing different levels (0.0 [control], 0.5, 1 and 2%) of SA. The skin mucus total immunoglobulin and total protein levels in fish fed 2% SA showed significant increase compared to the control group (P<0.05). Results showed a significant increase in the GH gene expression in 1 and 2% SA treatments (P<0.05). The carps fed the diet with 2% SA showed a significant increase in IGF-1 expression (P<0.05). The expression of GSTa, and GPX (antioxidant genes) revealed a significant increase in the GSTa (fish fed SA at 1% and 2% levels) and GPX gene expression with fish fed 2% SA (P<0.05). Supplementation of fish diet with SA induced a slight elevation in the intestine of all immune-related genes (TNF-α, IL-1β, IL8 and Lyz) compared to the control group (P>0.05). However, Lyz gene was significantly up-regulated in 1 or 2% SA treatments. These results confirmed beneficial effects of SA as a feed additive in common carp culture.

Four diets were prepared to include a mixture of medium-chain fatty acids and taurine as a digestive/ metabolic enhancer (DME, AQUAGEST^®) at 0, 1, 2, and 3 g DME/kg diet and fed to common carp (initial weight, 4.55±0.03 g) for 70 days. Dietary DME significantly increased the final weight, weight gain, specific growth rate, feed intake, and protein efficiency and decreased feed conversion ratio in a dose-dependent manner (P<0.05). The body lipid composition was significantly improved by feeding DME at 2 g/kg diet (P=0.0141). The intestine villus length and the number of goblet cells were significantly increased in fish fed 2 g DME/kg diet (P<0.05). The intestinal villi displayed increased length, branching, and density by supplementing DME to common carp diets. Fish fed DME at 2 g/kg diet displayed markedly decreased aspartate aminotransferase (AST) and alanine aminotransferase (ALT ) (P=0.025 and P=0.043) and increased total protein and globulin (P =0.002 and P=0.003). Additionally, fish fed 2 and 3 g DME/kg levels displayed significantly increased albumin levels (P=0.006). Lysozyme and phagocytic activities were increased by feeding DME at 2 g/kg diet, while the phagocytic index increased by 2 and 3 g/kg diet (P<0.05). The optimal supplementation level of DME is 1.63 to 2.05 g/kg for common carp based on the polynomial regression analysis. In conclusion, common carp fed diets with a mixture of medium-chain fatty acids and taurine displayed improved growth, digestion activity, and immune response.

The present study was aimed to evaluate the effects of different levels of salinity on water quality, growth performance, survival rate and body composition of Pacific white shrimp in a heterotrophic/ biofloc technology (BFT). Shrimp post-larvae with an average weight of 74.46 mg were cultured in 300 L fiberglass tanks containing 130 L water at a density of 1 post-larva/L. Three treatments including different levels of salinity of 8, 21 and 32 ppt with three replicates were considered. The highest levels of body weight, growth rate, specific growth rate, increase in body length and survival rate were observed at high salinity level (32 ppt). The highest feed conversion ratio (FCR) and the lowest level of feed efficiency were obtained in shrimps cultured at lowest salinity level (P<0.05). Biochemical analysis of shrimp body composition showed an increase in protein, lipid and ash content as the salinity was elevated (P<0.05). The zero-water exchange system used in this study had no significant effects on water quality parameters. The results of the present study concluded that high salinity level (32 ppt) improves the growth and survival of the biofloc supplemented Pacific white shrimp in a BFT system.

The aim of this study was to determine the concentrations and emissions of greenhouse and odorous gases in different types of dairy cattle housing systems with the use of Fourier-transform infrared (FTIR) spectroscopy. The study was performed in autumn and winter in four types of dairy cattle barns with different process and technical systems (free-stall, deep litter – FS-DL; free-stall, sub-floor manure storage – FS-SFM; free-stall, litter in stalls – FS-LS; tie-stall, litter in stalls – TS-LS) in northern Poland. Analyses of gaseous mixtures in barn air were conducted by infrared spectrometry with the multi-component Gasmet DX4030 analyzer. A total of 200 measurement spectra were acquired and subjected to qualitative and quantitative analyses with the Calcmet Professional program with a library of reference spectra for 200 chemical compounds. The results of the study indicate that housing systems and the technological solutions applied in barns exert a considerable influence on the production of greenhouse and odorous gases. Free-stall housing with slatted floors and sub-floor manure storage appears to be the optimal solution for reducing the animals’ exposure to the presence of the analyzed chemical compounds in air, improving animal welfare and minimizing GHG emissions to the environment (considering the optimal ventilation rate). It should be noted that the concentrations of other potentially harmful compounds, for which the maximum safe levels have been specified, were also relatively low in the remaining systems, which points to the observance of high sanitary standards and the use of efficient ventilation systems in the evaluated barns.

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.