Volume 20 (2020): Edizione 1 (January 2020)

Circular RNAs (circRNAs) have been identified in the skeletal muscle of numerous species of animals. Their abundance, diversity, and their dynamic expression patterns have been revealed in various developmental stages and physiological conditions in skeletal muscles. Recently, studies have made known that circRNAs widely participate in muscle cell proliferation and differentiation. They are also involved in other life processes such as functioning as microRNA (miRNA) sponges, regulators of splicing and transcription, and modifiers of parental gene expression with emerging pieces of evidence indicating a high chance of playing a vital role in several cells and tissues, especially the muscles. Other research has emphatically stated that the growth and development of skeletal muscle are regulated by proteins as well as non-coding RNAs, which involve circRNAs. Therefore, circRNAs have been considered significant biological regulators for understanding the molecular mechanisms of myoblasts. Here, we discuss how circRNAs are abundantly expressed in muscle (myoblast) and their critical roles in growth and development.

The feed industry has attempted to encourage the animal husbandry sector to feed complete concentrate pellets containing ground grains in ruminant nutrition and thus prevent farmers from making concentrate in their farms. Reducing particle size using pre-pelleting grinding and pressing materials during pellet formation, plus starch gelatinization by heat treatment in the conditioner are key factors determining the extent and rate of starch digestion in ingested pellets. If prepelleting grinding of corn and barley grain for using in the pelleted concentrate results in ground materials of less than 1.8 mm mean particle size (especially in the case of barley grain which is highly fermentable), then it increases the rate of fermentability in the rumen which in turn increases the acidosis risk. Such situation and dissatisfaction from pellets feeding to ruminant have directed farmers to produce homemade mash concentrate which may include steam-flaked form of grains in the concentrate mixture. Pelleting process increases the time needed to collapse the pellet in the rumen so delays the access of microbes to fermentable organic matter. This counterbalance property highly depends on pellet size with highest effect obtained using 10 mm diameter pellets for cattle. Feeding separately steam-flaked grains (plus other pelleted/mash non-grain ingredients of concentrate) may give results similar to the complete concentrate pellets having ground grains prepared according to optimized recommendations (pellet diameter and grain mean particle size). Nonetheless cost benefit studies are necessary to adopt one of the above two optimized technologies that has higher starch utilization and lower fecal starch excretion by animal. In the situation where consuming steam-flaked grains has priority of application in the diet, it is strongly recommended to pellet non-grain portions of concentrate for obtaining numerous pellet advantages such as reducing transportation cost, dust, sorting and bird removal.

Health of the intestine is one of the main reasons that affects the bird’s performance, and thus the economic yield in the poultry sector. Various studies have examined how to improve the intestinal health using dietary supplements, including organic acids such as sodium butyrate (SB). The efficacy of the dietary supplementation in poultry is often assessed using an important parameter such as intestinal integrity, which is often assessed as a measure of high villus height and the ratio of villus height to crypt depth, or count of goblet cell numbers. In broilers, the villus length and width were increased by the addition of dietary SB. Since, at day 21 and 42, the villus length was increased by 55 and 27%, and 39 and 18% for birds fed 0.5 and 1 g/kg, respectively, compared with the control diet. Furthermore, SB plays an important role in development of poultry intestinal epithelium. It can be employed by the intestinal epithelial cells as an energy source to stimulate their differentiation and proliferation, and to improve intestinal barrier function. SB is effective against acid intolerant species such as Salmonella, Clostridium perfringens and E. coli. In addition, use of butyric acid at 0.6% reduced the pH of gastrointestinal segments. For this, SB could be a potential alternative in maintaining the health of gastrointestinal tract and improving the productive performance of poultry. This review refers to the expanding horizons in the research on SB supplementation in poultry health and nutrition.

The p38MAPKs (mitogen-activated protein kinases) signaling contributes a pivotal role in mammalian ovarian follicular development; however, the knowledge regarding their expression in geese remains unresolved. The objective of the current study was to determine the spatio-temporal expression of heat shock protein 27 (HSP27) and mitogen- and stress-activated protein kinase 1 (MSK1) genes in the prehierarchical follicles during geese ovarian development. The prehierarchical follicles samples were harvested from 35- to 37-week-old healthy laying geese. HSP27 and MSK1 relative expression in various sized prehierachical follicles was detected by real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting. Follicular wall localization of HSP27 and MSK1 was examined by using immunohistochemistry. Our results at mRNA level indicated that HSP27 was highly expressed in middle white follicles whereas MSK1 was predominantly expressed in small white follicles. The western blotting results for HSP27 and MSK1 were inconsistent with the RT-qPCR results in various stages of prehierachical follicular development but noticeably, HSP27 proteins were still expressed more in middle white follicles while MSK1 proteins were more abundant in primary follicles. At different stages of prehierarchical development, immunodetections in the granulosa and theca cells revealed that HSP27 was intensively localized in middle white follicles while strong detections of MSK1 were observed in large white follicles. These results indicate HSP27 and MSK1 might be associated to the key regulators of folliculogenesis in geese.

The yellow-feather broiler is a popular poultry breed in Asia, particularly in China. In this study, we performed RNA-seq analysis to identify differentially expressed genes (deGs) in the liver of yellow-feather broilers that had been subjected to acute heat stress treatment (38±1°C for 4 h, recovery 2 h) and determine the response of the liver to high temperature and its effects on yellow-feather broiler physiology. We found that the cloacal temperature and respiratory rate of yellow-feather chickens were significantly increased immediately after the initiation of acute heat stress (38°c) treatment. And after recovery for 2 h, there was no difference in the cloacal temperature and respiratory rate between the acute heat stress and control groups. A total of 834 DEGs were observed in response to heat stress by RNA-seq. Almost half of the DEGs were involved in the lipid and energy metabolism, including fatty acid metabolism (ACOX1, ACACA, ACSL1, ACSL6, ACAA1, ACAA2, HADHB, and FASN) and propanoate metabolism (ACSS2, ALDH2, ACACA, DLAT, ALDH7A1, MDH1, ME1, ABAT, SUCLG2, and ACSS3). Our findings provide the context for RNA-seq studies in the liver of yellow-feather chickens and suggest that the liver of yellow-feather broilers has the lipid and energy metabolism physiological mechanisms activated in response to heat stress.

Inbreeding was analysed in a population of 14,144 Polish Black-and-White Holstein-Friesian (PBWHF) young bulls born between 1994 and 2017 and bred under both conventional and genomic breeding programmes. The inbreeding coefficients were computed using a model with genetic groups, according to the algorithm given by VanRaden. It was found that in the analysed population all bulls are inbred (100% of the population), with the mean coefficient of inbreeding ranging from 0.09% to 26.95%. Pedigree analysis also showed a relationship between the changing number of bulls over the years and the dynamics of population inbreeding. These trends are connected with changes in the breeding scheme, related to the implementation of genomic selection in the breeding programme for PBWHF cattle in 2014. The increasing number of weaned young bulls in Poland was paralleled by a fairly consistent increase in the mean inbreeding, but the inbreeding dynamics were relatively small. A reverse trend was observed in the group of young bulls born after 2013. As the number of bulls very rapidly decreased in successive birth years, the mean inbreeding for successive birth-year groups very rapidly increased. As a result, the estimated linear trend was equal to 0.02% inbreeding per year of birth in the group of bulls raised before genomic selection (~20 birth-year) whereas in the group of bulls raised after genomic selection (~4 birth-year) the trend was much higher and amounted to 0.56% inbreeding per year of birth. The high mean inbreeding found in the group of the genomically selected young bulls may translate into higher inbreeding in the whole population of PBWHF cattle, because these bulls are now intensively used as sires. The results of our study also show that the implementation of genomic selection in the breeding programme caused a very rapid increase in the inbreeding rate per birth-year in young bulls.

The use of a non-invasive approach to collect biological samples from natural populations represents a great means of gathering information while avoiding handling animals. Even if corticosterone is the main glucocorticoid investigated in birds, there has been observed a proportional direct link between corticosterone and cortisol concentrations. Dehydroepiandrosterone (DHEA) can be produced by the adrenal cortex and should have prominent antiglucocorticoid properties also in birds. The aim of this study was to verify if there is any difference in the cortisol and DHEA feather concentrations between clinically normal and physiologically compromised Griffon vultures (Gyps fulvus) through the non-invasive approach of collecting moulted feathers without having to pluck them from the bird. The study was carried out using 8 physiologically compromised (PC) Griffons and 9 clinically normal Griffons considered as the control (CTRL) group that were necropsied or from the wildlife rehabilitation centre. Primary and secondary covert feathers were either collected directly from the birds’ cage floors, or, in the case of dead Griffons, they were plucked off the animals. The results, obtained by RIA, revealed that both cortisol (P<0.01) and DHEA (P<0.05) feather concentrations were higher in the PC than in the CTRL group. No difference was observed by comparing the cortisol/DHEA ratio between the two evaluated groups (P=0.15). Pearson’s correlation coefficients showed no correlation between feather hormone concentrations in the PC group (r=0.01, P=0.96) while a positive correlation in the CTRL group (r=0.65, P=0.006) was observed. In conclusion, our study reveals that moulted feathers can be a non-invasive and an interesting tool to evaluate the allostatic load of wild birds and they allowed better understanding the relationship between hormones of the hypothalamic–pituitary–adrenal axis and the physiological status of the birds.

In this study, the effect of trichostatin A (TSA)-mediated epigenomic modulation of nuclear donor cells on the in vitro developmental potential of caprine somatic cell cloned embryos was examined. The enucleated ex vivo-matured oocytes were subzonally injected with adult ear skin-derived fibroblast cells exposed or not exposed to TSA (at a concentration of 50 nM). The experiment was designed on the basis of three different approaches to TSA-dependent modulation of donor cell-descended genome: before being used for somatic cell nuclear transfer/SCNT (Group I); immediately after activation of nuclear-transferred (NT) oocytes (Group II); or combined treatment both before being used for SCNT and after activation of NT oocytes (Group III). In the control Group IV, donor cell nuclei have not been treated with TSA at any stage of the experimental design. In TSA-treated Groups I and II and untreated Group IV, cleavage activities of cloned embryos were at the similar levels (80.6%, 79.8% and 77.1%, respectively). But, significant difference was observed between Groups III and IV (85.3 vs. 77.1%). Moreover, in the experimental Groups I and III, the percentages of cloned embryos that reached the blastocyst stages remarkably increased as compared to those noticed in the control Group IV (31.2% vs. 36.7% vs. 18.9%, respectively). In turn, among embryos assigned to Group II, blastocyst formation rate was only slightly higher than that in the control Group IV, but the differences were not statistically significant (25.8% vs. 18.9%). To sum up, TSA-based epigenomic modulation of somatic cell-inherited nuclear genome gave rise to increased competences of caprine cloned embryos to complete their development to blastocyst stages. In particular, sequential TSA-mediated modulation of both nuclear donor cells and activated NT oocytes led to improvement in the blastocyst yields of cloned goat embryos, which can result from enhanced donor cell nuclear reprogrammability.

MicroRNAs (miRNAs or miRs) belong to a class of small non-coding RNAs of 19 to 24 nucleotides long that act as negative gene regulators at the post-transcriptional level. Quantitative PCR (q-PCR) is a commonly used technique in the profiling of miRs, and identification of reliable endogenous controls is crucial for proper data normalisation. To date, no study has been performed on reference miRs for the normalisation of miR expression in chicken ovarian tissues. Therefore, the aim of the present study was to experimentally identify the most stable reference mirs for normalisation of miR q-PCR expression data in the chicken ovary. Relying on high-throughput sequencing, five putative reference miR (let-7a-3p, miR-140a-3p, miR-22-5p, miR-33-5p, miR-99a-3p) were identified and subsequently analysed in a total of 66 tissue samples. The stability of candidate endogenous controls validated by the most widely used algorithms, geNorm, NormFinder, and BestKeeper, showed that let-7a-3p, miR-140a-3p, and miR-22-5p are the most appropriate choice of reference genes. Application of different normalisation approaches to the relative quantitation of randomly chosen miR-1552-5p in chicken ovarian follicles indicated the impact of the selected reference genes on miR expression. Further, the results revealed a downregulation of miR-1552-5p. In summary, the three identified endogenous reference miRs are suitable for profiling the miR expression in ovarian tissues of laying hens. Our findings provide valuable information for future miR expression studies in the avian ovary.

The degree of flesh pigmentation is one of the most important quality criteria dictating the fish market value. It is well known that fish, like other animals, cannot synthesize their own coloring pigments de novo, and must obtain these pigments from their diet. In this study, four levels of black mulberry (Morus nigra) juice powder (BMP) as a natural pigment source were incorporated into a basal diet at concentrations of 0, 0.25, 0.5, and 0.75% and fed to rainbow trout weighing 100±5 g for 8 weeks in triplicate. At the end of the feeding trial, the effect of BMP on growth performance, blood biochemical parameters and fillet color was examined. Fish fed BMP showed significant enhancements in weight gain (WG), specific growth (SGR), food conversion ratio (FCR), and survival rates (SR) (P<0.05). SGR, WG and SR values were increased significantly following dietary supplementation with BMP in a dose dependent manner with the highest values in fish fed 0.75%, while the FCR was decreased (P<0.05). Body crude protein, lipid, and moisture contents were increased significantly in fish fed BMP (P<0.05). Dietary BMP has significantly decreased the levels of blood ALT, AST, and glucose (P>0.05). While the blood carotenoid concentration was increased in fish fed 0.5% BMP compared to other treated groups. Fish fed BMP showed increased fillet yellowness (b*) and redness (a*), while the fillet lightness (L*) was decreased when compared to the control (P<0.05). In conclusion, diets supplemented with BMP increased the growth performance, muscle pigmentation, and health status of rainbow trout.

The aim of this study was to evaluate the effects of different levels of dietary Lactobacillus plantarum as probiotic (Pro) with bovine lactoferrin (LF) and xylooligosacharide (XOS) on growth performance, hemato-immune response, body composition, digestive enzymes activity and expression of immune-related and growth-related genes of sobaity (Sparidentex hasta) for 8 weeks. Fish were fed with feed including: control diet (no LF, XOS and pro inclusion), diet 1 (400 mg kg⁻¹ LF + 5000 mg kg⁻¹ XOS), diet 2 (400 mg kg⁻¹ LF + 10000 mg kg −1 XOS), diet 3 (400 mg kg⁻¹ LF + 1 × 106 gr⁻¹ Pro (L. plantarum)), diet 4 (800 mg kg⁻¹ LF + 5000 mg kg ⁻¹ XOS), diet 5 (800 mg kg⁻¹ LF + 10000 mg kg⁻¹ XOS), diet 6 (800 mg kg⁻¹ LF + 1 × 106 gr⁻¹ Pro (L. plantarum)). Growth performance, hematological parameters (except for white blood cell counts), body composition and immune-related gene expression were not affected by different experimental groups (p>0.05). Nonetheless, non-specific immune response (except for total immunoglobulin) and growth-related gene expression of treatments and control group significantly varied (P<0.05). Digestive enzymes activity including total protease and amylase increased by supplementing diets with different combinations of immunostimulants (P<0.05). Our results suggest that diets supplemented with selected levels of LF, XOS and L. plantarum could not improve growth performance, body composition and hemato-immune response, but improved digestive enzyme activities in S. hasta fingerlings.

In the present study, the complete cycle of the preconsumer waste transition by black soldier fly larvae (BSFL) into sustainable raw material (dietary fat) for broiler chickens was examined. In two individual experiments, the effects of selected rearing medium made from various preconsumer wastes on the nutritive value and performance of BSFL were tested (1st trial). In the second experiment, partial (25, 50, or 75%) or total replacement of soybean oil fed to broiler chickens by BSFL fat obtained via supercritical CO₂ extraction from larvae from the 1st experiment was conducted. In the performance trial on birds, nutrient digestibility, selected gastrointestinal tract (GIT) segments, internal organ traits, and welfare status were also measured. In the first trial, 1-day-old BSFL were allotted to 5 treatments (8 replicates each). The following substrates were tested, i.e., wheat bran, carrots, cabbage, potatoes, and a mixture of the previously mentioned organic food wastes (equal ratio of each). In the second experiment, a total of 960 day-old female Ross 308 chicks were randomly assigned to 5 dietary treatments (16 replicates and 12 birds per replicate). The following groups were applied: SO – 100% soybean oil, HI25 – a mixture containing 25% BSFL fat and 75% SO, HI50 – addition of BSFL and SO in a 50:50 ratio, HI75 – a mixture containing 75% BSFL fat and 25% SO, and HI100 – 100% BSFL fat. The results of the present study showed high variability in the chemical composition of insects among groups (410 vs. 550 g kg⁻¹ CP; 60 vs. 170 g kg⁻¹ EE), as well as a significant influence of rearing substrate composition on BSFL performance, i.e., the average mass of 100 randomly chosen larvae (P<0.001), waste reduction rate (P<0.001), and conversion rate (P=0.008). Moreover, the partial or total replacement of SO by BSFL fat did not affect (P>0.05) the growth performance, coefficients of apparent ileal digestibility of nutrients, selected organ weights and length, or the welfare status of the broilers. In conclusion, it is possible to obtain an environmentally friendly, sustainable energy source from BSFL biomass and implement it in broiler diets without a negative effect on the birds’ production.

The aim of the study was to assess the gut microbiota and selected haematological and biochemical blood parameters of weaned piglets following dietary supplementation with a probiotic and vitamin C. the piglets were divided into a control group (group C) and an experimental group (group E), with 30 piglets in each group. All animals received the same feed ad libitum. The animals in the control group (group C) received feed with no added probiotic and vitamin C. the piglets in the experimental group (group E) were given a supplement containing a probiotic (Bacillus cereus 1×10⁹ CFU/kg) in the amount of 1.5 g/piglet/day and vitamin c in the amount of 300 mg/piglet/day. The supplement was administered for 28 days. The total numbers of bacteria of the family Enterobacteriaceae and of the genus Lactobacillus were determined in faeces. The erythrocyte count, haemoglobin level, haematocrit, leukocyte count, and percentages of neutrophils and lymphocytes were determined in the blood. The biochemical analysis concerned the concentration of triacylglycerols, total cholesterol, and LDL and HDL cholesterol. In group E a significant decrease (P<0.01) in the total number of Enterobacteriaceae bacteria was observed in the faeces of the piglets, accompanied by an increase in the number of lactobacilli relative to group C. E. coli was found to predominate over other microorganisms. Salmonella choleraesuis bacteria were present in the faeces of both groups before administration of the supplement, but were not found after its use. The supplement with probiotic and vitamin C caused a significant increase in the erythrocyte, haemoglobin and haematocrit levels in the blood of the piglets and a significant decrease in the concentration of triacylglycerols, total cholesterol and LDL cholesterol.

The aim of the study was to test whether the use of probiotic bacteria Bacillus subtilis or Enterococcus faecium or a phytobiotic containing cinnamon oil can improve the metabolic parameters, immune status, gut microbiota and histology, and growth performance of broiler chickens. The experiment was carried out on 560 one-day-old male Ross 308 broiler chickens raised until the age of 42 days. The broiler chickens were assigned to 4 experimental groups of 140 birds each (7 replications of 20 individuals each). The control group (Control) did not receive additives. A probiotic preparation containing live bacterial cultures of Enterococcus faecium (EF, in the amount of 0.25 g/l) or Bacillus subtilis (BS, 0.25 g/l) or a phytobiotic preparation containing cinnamon oil (OC, 0.25 ml/l) was administered to the broiler chickens with their drinking water throughout the rearing period. The most important results indicate that the use of BS and OC resulted in: a significant (P≤0.05) increase in the level of ferric reducing ability of plasma (FRAP), high-density cholesterol (HDL) and glutathione (GSH + GSSH) and a significant (P≤0.05) decrease in the level of malondialdehyde (MDA), lipid hydroperoxides (LOOH), total cholesterol (TC), triacylglycerols (TAG), nonesterified fatty acids (NEFA) and interleukin 6 (IL-6), a ratio of heterophils : leukocytes (H:L) and alkaline phosphatase (ALP) activity, alanine aminotransferase (ALT), acidic phosphatase (AC) and creatinine kinase (CK), relative to the C group. In the blood of broiler chickens from the OC treatment, aspartate aminotransferase (AST), lactate dehydrogenase activity and 3-hydroxy-butyrate dehydrogenase (HBDH) significantly (P≤0.05) decreased in relation to the C group, and in broiler chickens from EF and BS treatments there was an increase (P≤0.05) in haemoglobin (Hb) content. Compared with group C, in the broiler chickens’ nutritional content from EF, BS and OC treatments, the total number of coliforms and number of fungi significantly (P≤0.05) dropped and the number of aerobic bacteria increased (P≤0.05) in the length of the villus and the depth of the crypt. It has been found that Bacillus subtilis, Enterococcus faecium and phytobiotic containing cinnamon oil can improve the microbiological and histological appearance of broiler chicken intestine. The addition of probiotic bacteria Bacillus subtilis or phytobiotic containing cinnamon oil to drinking water is more preferable than Enterococcus faecium regarding stimulation of the immune system, blood redox status parameters, parameters of metabolic changes and the gut microbiome and morphometry.

This experiment was conducted to establish the effects of two types of microalgae [Chlorella vulgaris (AI), C. variabilis (AII) and their combination (AI+AII)] with two substrates (wheat and corn silages) on rumen fermentation, gas and methane production. To each substrate, one of 3 algae treatment was supplemented at 0% and 25% of the total incubated dry matter. A series of 5 measurement points (3, 6, 12, 24 and 48 h) were completed and the gas production was monitored. The proximate and mineral composition of microalgae and substrates were examined. At 48 h incubation rumen fermentation variables and CH₄ production were also assessed. When compared with wheat silage, corn silage caused an increase in gas production (P<0.05). Ruminal gas production decreased in the algae groups when compared to the controls (0% algae, wheat and corn silages, P<0.05). Among algae, C. vulgaris had the strongest effect, decreasing gas production by 34%. Among algae, the total volatile fatty acids (VFA) and CH₄ production were found to be lower in C. variabilis (P<0.001). Ammonia-N increased with the algae inclusion (P<0.05). But, the ruminal gas production, pH, acetate, the total VFA, CH₄ and rumen fermentation efficiency were not affected by the substrate and algae interaction (P>0.05). The propionate was the highest (P<0.05) for corn silage when incubated with C. vulgaris. Ruminal butyrate was the lowest for the wheat silage when incubated with the mixture of algae (P<0.05). The NH₃-N was the highest in corn silage when incubated with all algae types (P<0.05). Careful selection and combination of substrate and algae may positively manipulate rumen fermentation and may inhibit CH₄ production. Further research is needed to validate these results in vivo.

A total of 211 pheasants (Phasianus colchicus) were reared using two different production systems (free range and intensive) to determine the effect of production system and slaughter age on growth performance and carcass traits. Birds were slaughtered at 14, 16, and 18 weeks of age. Production system did not significantly affect body weight until 18 weeks; at this age, pheasants reared in free range exhibited a higher average weight (1149 g vs. 1012 g). Total feed consumption and feed conversion ratios did not differ among production systems. The most in-demand portions of the carcass (breast and leg) were not affected by differences in production system. The leg and breast proportions which were the most edible parts of the carcass were around 26% and 35%, respectively, in both free-range and intensive systems.

This study evaluated myosin heavy chain composition and the effect of aging time (45 min, 24 h, 96 h and 168 h) on meat quality parameters and dystrophin and integrin degradation pattern in longissimus thoracis and psoas major muscles of 24 Polish Landrace fatteners slaughtered at 100 kg body weight. It was found that m. longissimus thoracis had a greater percentage of MyHC-IIB (P≤0.05) and a significantly lower percentage of type I and IIA/IIX (P≤0.05) compared with the m. psoas major. Moreover, psoas major muscle had significantly higher (P≤0.05) pH₄₅, pH₂₄ and lower drip loss values for 45 min to 24 h, 45 min to 96 h and 45 min to 168 h than m. longissimus thoracis. Muscle type also had a significant effect on the rate of dystrophin and integrin degradation postmortem, which were significantly (P≤0.05) more rapidly degraded in the m. longissimus thoracis compared to the m. psoas major. It is concluded from the obtained results that the muscles with a greater percentage of MyHC-IIB show lower pH values, which translates into more rapid rate of integrin and dystrophin degradation. Ultimately, this may contribute to higher drip loss values during refrigerated storage.

Deer meat is a high quality and valuable food for human consumption. It has high nutritive value because of its high protein and heme iron content, and low levels of fats and saturated fatty acids. The aim of this study was to examine the quality parameters of meat from fallow deer and roe deer that were hunted in Serbia. Parameters studied were live weight, carcass weight, chemical composition of meat, color, fatty acid content of meat, volatile compounds, and sensory characteristics. The results obtained show no significant difference in the chemical composition of these two species of deer meat, but there were differences regarding fatty acid content, volatile compounds, color and sensory properties of meat. The ratios of polyunsaturated to saturated fatty acids in the deer meat ranged from 0.387 to 0.556. The results suggest that deer species has a significant impact on the fatty acid profile and content of volatile compounds of deer meat.

Meat is an important part of the human diet since it provides several nutrients. However, the amount of these nutrients can differ according to several factors. With this in mind, the present research was designed with the main objective of evaluating the effect of production system of broiler chickens (industrial, range and organic) on meat quality. The physicochemical, chemical and nutritional characteristics were determined in breast and drumstick meat. The organic chickens presented the lowest amounts of fat and cholesterol and the highest amounts of protein. The colour was also influenced by the production system, where organic and range chickens had the highest values of redness in both cuts (breast and drumstick). In addition, the content of essential fatty acids (C18:2n-6 and C18:3n-3) and other fatty acids with high biological importance, such as eicosapentanoic acid (EPA; C20:5n-3), docosapentanoic acid (DPA; C22:5n-3) and docosahexanoic acid (DHA; C22:6n-3) were higher in organic samples compared to industrial or range chickens. The amino acids content did not vary with the production system. With regard to mineral contents, organic chickens had the highest values of iron in drumstick and significantly lower values of magnesium in both cuts than industrial chickens. On the whole, the meat of the organic chickens showed better nutritional characteristics than those produced in range or industrial conditions.

The aim of the study was to compare the content of selected bioactive whey proteins and lipophilic vitamins, which largely determine the bioactive status of milk, in milk obtained from local breeds of cows raised in Poland (Polish Red, White-Backed and Simmental) and Polish Holstein-Friesian cows. Basic chemical composition and content of selected bioactive compounds (β-lactoglobulin, α-lactalbumin, lactoferrin, bovine serum albumin, and vitamins: E, A, D₃ and β-carotene) in 550 milk samples were analysed. The milk produced by local breeds proved to be a more valuable source of whey proteins and lipophilic vitamins than that of the Polish Holstein-Friesians. It was distinguished by its content of all bioactive compounds, including those with antioxidant properties, i.e. vitamins E, A and D₃ and β-lactoglobulin, and antimicrobial properties, mainly lactoferrin. Therefore, the milk of cows of local breeds should be considered a valuable material for processing, especially at the level of the farm or small local processing plant, to produce products that are richer in health-promoting compounds. The promotion of milk from local breeds can therefore be an opportunity for the farms that raise them.

The aim of the research was to assess the quality of milk from mountain sheep used for the production of traditional cheeses, taking into account the influence of the breed, the month of milking, and the content of somatic cells. Milk for the study was obtained from sheep of three mountain breeds: Podhale Zackel (PZ), Polish Mountain Sheep (PMS), and Coloured Mountain Sheep (CMS). The sheep were grazed in mountain pastures after lamb weaning, in the period from May to October in the traditional system. No influence of the breed on the examined parameters was found, except for urea content. Mountain sheep milk was characterized by a content of 19.68% solids, 8.48% fat, 6.63% protein, in which almost 76% was formed by casein (4.99%), and the average lactose content was 4.15%. Other milk parameters also did not differ between breeds: density was 1034.04 g/L, acidity 11.34°SH, and mean somatic cell content was 982.13∙10³∙ml⁻¹ (log₁₀SCC = 5.68). The highest urea content was recorded in the milk of Coloured Mountain Sheep (280.69 mg/L) and the lowest urea content was recorded in the milk of Zackel sheep (200.97 mg/L). The month of milking influenced the content of most milk components, but no changes in SCC content during lactation were found. Significant correlations between fat content and other milk parameters were recorded. In the case of urea content, negative, statistically significant correlations with the majority of examined parameters were found.