Volume 21 (2021): Issue 2 (April 2021)

Heat stress in livestock is a function of macro- and microclimatic factors, their duration and intensity, the environments where they occur and the biological characteristics of the animal. Due to intense metabolic processes, high-producing dairy cows are highly vulnerable to the effects of heat stress. Disturbances in their thermoregulatory capability are reflected by behavioural, physiological and production changes. Expression of thermoregulatory behaviour such as reduction of activity and feed intake, searching for a cooler places or disturbances in reproductive behaviours may be very important indicators of animal welfare. Especially maintain of standing or lying position in dairy cattle may be a valuable marker of the negative environmental impact. Highly mechanized farms with large numbers of animals have the informatic system can detect alterations automatically, while small family farms cannot afford these type of equipments. Therefore, observing and analysing behavioural changes to achieve a greater understanding of heat stress issue may be a key factor for developing the effective strategies to minimize the effects of heat stress in cattle. The aim of this review is to present the state of knowledge, over the last years, regarding behavioural changes in dairy cows (Bos Taurus) exposed to heat stress conditions and discuss some herd management strategies provided mitigation of the overheat consequences.

Interspecific hybrids called hybrids are individuals obtained by crossing two different species. Hybrids are found both in nature among wild animals but also have become attractive in animal husbandry due to the high production features of the F1 generation. Interspecific hybrids are observed in nature most often as a result of crossing closely related species, which is a great danger to the purity of the population of starting species. Interspecies hybrids are also created by man for production purposes. Due to disturbances in gametogenesis processes, they have become a valuable research model. In the article, we describe interspecific hybrids occurring in nature and related problems, interspecific hybrids created for production purposes in animal husbandry, but also research using hybrids as a research model. In the article we also highlight the issues of fertility of individuals obtained from such matings.

Livestock buildings are often contaminated with bacterial and fungal microflora. Animals living in the buildings, especially their excreta and secretions and their feed, can be a source of microorganisms, including pathogens. Significant microbial contamination occurs in pig houses, poultry houses and cowsheds. The microbes most frequently isolated from the air of these buildings are bacteria of the genera Streptococcus, Staphylococcus, Bacillus, and Clostridium and of the family Enterobacteriaceae. Among fungi, the most common are Aspergillus, Trichoderma, Penicillium, Cladosporium and Alternaria. Microbes present in livestock buildings often pose a hazard to workers, in whom they can cause infectious and allergic diseases, especially respiratory disease. Bacterial endotoxins may also pose a threat to humans and animals. For this reason it is important to carry out microbiological monitoring and preventive measures on livestock farms and to maintain appropriate environmental conditions. This will reduce microbiological contamination of livestock buildings and improve both workers’ health and animal welfare.

The rearing of piglets is the most difficult period in the pigs’ production because of their poorly developed digestive system and the low activity of digestive enzymes. Problems in nutrition and stress cause some disorders in the functioning of the digestive system leading to diarrhea and the mortality of piglets. Starting in 2006 in the EU, a total ban on antibiotics in their use as growth promoters was introduced. Since then, new and safe feed additives have been sought in order to replace antibiotics. Organic and inorganic acids as well as their salts were recognized as effective and safe additives. Due to their properties, they can improve feed palatability and digestibility, reduce the buffer capacity of feed, impact the development and functioning of the pig’s digestive system and improve the health and growth parameters. However, the effectiveness of acids is related to their qualitative and quantitative share in the feed additive. In this review, some strategies for using organic acids, their mixtures and also some new multi-component products will be discussed.

Fur animal breeding has a long history. In many countries several fur animal species (including the red fox) have been recognized as livestock. The aim of this study was to estimate the pedigree parameters in the population of red fox on a Polish breeding farm. The data set consisted of information on 39 434 individuals, including 18 697 females and 20 004 males (733 animals were of unknown sex), from the years 1956–2016. The following pedigree parameters were estimated: average number of discrete generation equivalents, individual inbreeding coefficient, total and effective number of founders, effective population size, average relationship, founder genome equivalent, effective number of non-founders, and genetic diversity coefficient. The population size changed in successive years. The average inbreeding level was 5.34% for the population as a whole, and 6.04% for the inbred population. The estimated effective number of founders of the population was 84.18. The founder genome equivalent, which indicates the anticipated loss of genetic diversity caused by genetic drift, reached 9.59 in 2016 from an initial value of 34.22 in 1956. The loss of genetic diversity caused by the unequal contribution of the founder alleles did not change significantly over the years. Generally, the results indicate the good pedigree structure (including pedigree completeness) of the population studied. This implies reliable estimation of the inbreeding level, as one of the most important parameters in the genetic improvement programme.

Whole genome evaluation of quantitative traits using suitable statistical methods enables researchers to predict genomic breeding values (GEBVs) more accurately. Recent studies suggested that the ability of methods in terms of predictive performance may depend on the genetic architecture of traits. Therefore, when choosing a statistical method, it is essential to consider the genetic architecture of the target traits. Herein, the performance of parametric methods i.e. GBLUP and BayesB and non-parametric methods i.e. Bagging GBLUP and Random Forest (RF) were compared for traits with different genetic architecture. Three scenarios of genetic architecture, including purely Additive (Add), purely Epistasis (Epis) and Additive-Dominance-Epistasis (ADE) were considered. To this end, an animal genome composed of five chromosomes, each chromosome harboring 1000 SNPs and four QTL was simulated. Predictive accuracies in the first generation of testing set under Additive genetic architectures for GBLUP, BayesB, Baging GBLUP and RF were 0.639, 0.731, 0.633 and 0.548, respectively, and were 0.278, 0.330, 0.275 and 0.444 under purely Epistatic genetic architectures. Corresponding values for the Additive-Dominance-Epistatic structure also were 0.375, 0.448, 0.369 and 0.458, respectively. The results showed that genetic architecture has a great impact on prediction accuracy of genomic evaluation methods. When genetic architecture was purely Additive, parametric methods and Bagging GBLUP were better than RF, whereas under Epistatic and Additive-Dominance-Epistatic genetic architectures, RF delivered better predictive performance than the other statistical methods.

Baicalin is a flavonoid that has an influence on molecular processes. It possesses anticancer, anti-inflammatory, antiviral, antioxidative, and antithrombotic properties. It was found that baicalein treatment attenuated the damage of the mammary gland induced by LPS, suppressed the activity of myeloperoxidase, TNFα, and IL-1β in mice with mastitis. The aim of the study was a pilot analysis of baicalin tolerability after intramammary (IMM) administration and its impact on somatic cell count (SCC) after multiple IMM treatment on dairy cows with clinical mastitis. Moreover, the determination of baicalin in milk was performed by the sensitive ultra-high performance liquid chromatography with tandem mass spectrometry. The pharmacokinetic analyses were performed using Phoenix^® WinNonlin^® 6.4 and ThothPro v 4.1 software. Twelve dairy cows with clinical mastitis were selected for this study. The pharmacodynamic endpoint was SCC level and the clinical investigation was also carried out. Baseline SCC analysis was performed every 24 h among all cows three days before the first dose (B1–B3). After the baseline monitoring, 8 days of treatment (T1–T8) was performed and 8 days within recovery period SCC level was observed (R1–R8). Starting from T1 to T8, a decrease of SCC in relation to baseline was characterized by a declining trend. The presented results confirm the effect of baicalin on the reduction of SCC in mastitis in dairy cows after this therapy. The current study has shown that baicalin accumulation was not confirmed.

This study determined the influence of photoperiod on the expression of toll-like receptor 2 and 4 (TLR2 and TLR4), interleukin 1□ (IL1B), IL-1 receptor type I (IL1R1) and II (IL1R2), interleukin 6 (IL6), the IL-6 receptor (IL6R) and signal transducer (IL6ST), tumor necrosis factor α (TNF), and TNF□ receptor type I (TNFRSF1A) and II (TNFRSF1B) in the choroid plexus (ChP) of ewes with lipopolysaccharide (LPS)-induced acute inflammation. Under short-days (SD, n = 12, anestrous) and long-days (LD, n = 12, synchronized follicular phase), ewes were treated with saline or LPS. Compared to LD conditions, the ewes under SD were characterized by a greater (P<0.05) area under the curve (AUC) of cortisol in the LPS-treated group and by a lower (P<0.05) AUC of prolactin in the saline-treated group. Under both photoperiods, LPS increased (P<0.05) the expression of all examined genes except for TNFRSF1B (only under SD), TNF and TNFRSF1A (no stimulation), and IL6R (decreased (P<0.05) under SD). The LPS-induced increases in TLR2, TLR4, IL1B and its receptors, IL6 and TNFRSF1B were higher (P<0.05) under SD than LD. TLR4 was positively correlated with IL1B and IL6 in both saline- (r² = 0.64, P<0.01 and r² = 0.52, P<0.01) and LPS-treated (r² = 0.81, P<0.0001 and r² = 0.51, P<0.001) ewes. IL1B (r² = 0.56, P<0.01 and r² = 0.77, P<0.0001) and IL6 (r² = 0.77, P<0.005 and r² = 0.35, P<0.05) were positively correlated with TLR2 in saline- and LPS-treated ewes, respectively. This indicates that in ewes, the ChP response to acute systemic inflammation is dependent upon the photoperiod with stronger effects being observed under SD. Our results also suggest that gonadal hormones altering TLR4 signaling events are involved in the photoperiodic modulation of the ChP response to LPS. Further experiments are required to explain the mechanism involved in this phenomenon.

This study aimed to define potential markers that could determine the suitability of ejaculate for cryopreservation. Fresh semen from eleven boars (4–7 ejaculates/boar), regardless of their sperm motility, was subjected to a cryopreservation procedure. The sperm quality before and after freezing was assessed based on the sperm membrane permeability and acrosome integrity. The results showed that it was possible to effectively cryopreserve ejaculates below the accepted standards of 70–80% of fresh motile sperm and still obtain a high cryosurvival rate. Moreover, a significant correlation was found between the percentage of viable sperm with apoptotic-like changes, viable sperm with reacted acrosomes, and the cryosurvival rate. The proposed markers for assessing the quality of fresh semen could be used to predict the success of cryopreservation procedures.

Iron deficiency is the most common mammalian nutritional deficiency during the neonatal period. However, among mammalian species neonatal iron deficiency anemia (IDA), the most severe consequence of iron scarcity, occurs regularly in pigs. Although intramuscular supplementation of piglets with high amounts of iron dextran (FeDex) is largely considered an appropriate preventive therapy for IDA prophylaxis, an increasing evidence shows that it negatively affects pig physiology. The aim of our study was to evaluate the efficacy of non-invasive supplementation of piglets with sucrosomial ferric pyrophosphate (SFP), a highly bioavailable dietary iron supplement in preventing IDA, in humans and mice. Results of our study show that SFP given to piglets per os in the amount of 6 mg Fe daily efficiently counteracts IDA at a rate comparable with the traditional FeDex-based supplementation (100 mgFe/kG b.w.; i.m. injection). This was indicated by physiological values of red blood cell indices and plasma iron parameters measured in 28-day old piglets. Moreover, SFP-supplemented piglets showed significantly lower (P ≤0.05) plasma level of 8-isoprostane, a biomarker for oxidative stress compared to FeDex-treated animals, implying lesser toxicity of this order of iron replenishment. Finally, supplementation with SFP does not increase considerably the blood plasma hepcidin, a peptide that acts to inhibit iron absorption from the diet. SFP emerges as a promising nutritional iron supplement, with a high potential to be adopted in the postnatal period.

The present study evaluated the effects of dietary inulin on growth performance, body composition, serum, biochemical, and mucus immune factors; as well as innate immune responses of rainbow trout fry challenged with Aeromonas hydrophila. Four diets were prepared using a commercially available fish feed as a basal diet and different levels of prebiotic inulin incorporation; 0 (control), 1, 2, and 3%; referred to as C, T1, T2, and T3, respectively. The findings of the 60-day feeding trial showed that inulin inclusion affected final weight, food conversion rate (FCR), and specific growth rate (SGR) compared to that of the control group (P < 0.05), in which the lowest FCR was observed in T3. Body composition analysis revealed that inulin significantly increased protein content and decreased lipid levels, especially in the T1 and T2 groups. The lowest ash level was noticed in T2 (P < 0.05). Blood total protein, albumin, globulin, cholesterol, and glucose were not affected by inulin supplementation (P > 0.05). Analysis of humoral immune responses showed that the inulin supplements significantly increased lysozyme and complement activities (P < 0.05), as well as higher red blood cell count (RBC) and hemoglobin (Hb) in fish, fed 2% inulin, while no significant differences were observed among other treatments (P > 0.05). The mucosal parameters; including lysozyme, alkaline phosphatase (excluding ACH50); protease activities; and total immunoglobulin (IgM) improved significantly (P < 0.05), particularly in the T2 group. The T2 group also demonstrated the highest survival rate among all groups. The present findings indicate that dietary administration of inulin promotes growth and biochemical parameters, as well as serum immunity and mucosal immune responses of rainbow trout, in which a 2% inclusion produced the best results.

The present study investigated possible effects of dietary malic acid on the expression of immunity, antioxidant and growth related genes expression as well as skin mucus immune parameters in common carp. Common carp (Cyprinus carpio) fingerlings were fed diets supplemented with different levels (0 [control], 0.5%, 1%, 2%) of malic acid (MA) for 60 days. The results revealed highest expression levels of immune-related genes (tnf-alpha, il1b, il8 and lyz) in skin of common carp fed 2% MA (P < 0.05). Regarding 1% MA treatment comparison with control group, significant difference was noticed just in case of lyz (P < 0.05). Evaluation of growth related genes expression revealed no significant difference between treatments (P > 0.05). The study of antioxidant related genes (gsta and gpx) in common carp skin fed with MA, showed significant difference between treated groups and control (P < 0.05). Carps fed with 2% MA had highest alkaline phosphatase activity in skin mucus compared other treated groups and control (P < 0.05). There were no significant difference between 0.5% and 1% and control (P > 0.05). The study of total protein and total immunoglobulin (Ig) in common carp skin musus revealed no alteration following MA treatment (P > 0.05). The present data demonstrated that feeding with MA altered immune and antioxidant genes expression in skin mucus of common carp.

This study was conducted to examine the effects of the replacement of fish meal with defatted and fermented soybean meals on the growth performance, apparent nutrient digestibility, bile acid levels, and digestive enzyme activity of pompano Trachinotus blochii (Lacepède, 1801). Four diets were formulated to replace 40% of fish meal with defatted soybean meal (SBM), SBM fermented by Bacillus subtilis TH2 (FSBM1) or SBM fermented by B. subtilis B3 (FSBM2). The diets are denoted as follows: FMD (fish meal-based diet, used as a Control), SBMD (fish meal replaced by SBM diet), FSBM1D (fish meal replaced by FSBM1 diet), and FSBM2D (fish meal replaced by FSBM2 diet). Thirty fingerling pompanos with an initial body weight of 15.3 ± 0.3 g were allocated to each of eight indoor polyvinyl chloride tanks (500 L capacity), with two replicate tanks per dietary treatment. For 8 weeks, fish were hand-fed the experimental diets to apparent satiation twice daily. The final body weight, weight gain, specific growth rate, and feed conversion ratio of fish fed SBMD and FSBM1D were significantly inferior to those in fish fed FMD (P<0.05). These parameters were not significantly different between the FSBM2D and FMD experimental groups (P>0.05). Fish fed SBMD showed significantly lower plasma total cholesterol, whole body lipids, intestinal total bile acids and lipase activity than those fed FMD, whereas no significant differences were observed among fish fed FSBM1D, FSBM2D, and FMD. Trypsin activity and protein apparent digestibility coefficient were not significantly affected by the experimental diets. However, lipid apparent digestibility coefficient was significantly lower in fish fed SBMD and FSBM1D rather than FMD. There was no significant difference in lipid apparent digestibility coefficient between the FMD and FSBM2D experimental groups. The results indicated that SBM decreased bile acid levels, lipase activity, lipid digestibility, and growth performance in pompano fish. These parameters were increased by the inclusion of B. subtilis B3 fermented SBM in the diet, thus suggesting that fermentation of SBM with B. subtilis B3 may be an effective way to improve bile acid levels, lipase activity, lipid digestibility, and growth performance of pompano fed an SBM-based diet.

The beneficial effects of Bacillus subtilis C-3102 and Saccharomyces cerevisiae type 1 were tested in red sea bream (Pagrus major) feeds. A basal diet (control) and two other diets were prepared by supplementation with B. subtilis C-3102 (PB) or S. cerevisiae type 1 (PY). After 60 days, both probiotic-supplemented groups exhibited significant enhancement in growth performance, the protein efficiency ratio (PER), and digestive enzyme secretion (protease and amylase) compared to the control group (P<0.05). The anterior, middle, and posterior parts of the intestines exhibited significantly increased values of intestinal fold height (hF), enterocyte height (hE), and microvillus height (hMV) in fish fed PB- or PY-supplemented diets (P<0.05). Serum peroxidase, anti-protease, and bactericidal activities were enhanced significantly in both probiotic-treated groups compared to the control group (P<0.05). Serum and mucus lysozyme activities improved significantly in the PB group compared to the control group (P<0.05). Catalase activity was also significantly decreased in both probiotic groups, with relatively lower activity observed in the PY group (P<0.05). Both probiotic groups showed considerably increased tolerance to freshwater exposure (P<0.05). In conclusion, B. subtilis C-3102 and S. cerevisiae type 1 can be used as functional probiotics to enhance the growth performance, digestion capacity, gut morphology, immune response, and stress resistance of the red sea bream with relatively higher efficiency by B. subtilis C-3102.

This study investigated the effects of dietary supplementation with chestnut tannins (CNT) on metabolic and antioxidant status of prepartum cows along with their colostrum quality. Pregnant multiparous Holstein cows were paired according to parity and body condition score, and assigned either to a diet supplemented with 20 g/d of commercially available product containing chestnut tannins (CNT, n=20) or to an unsupplemented control diet (CON, n=20) for the last 25±2 d of pregnancy. Serum metabolite, insulin and antioxidant capacity indices were measured in blood samples taken at d 25 and d 5 before expected parturition. Chemical composition and IgG concentration were determined in colostrum samples collected from the first milking postpartum. The addition of CNT led to lower BUN (P=0.02) and consequently higher serum glucose (P=0.02) and insulin (P<0.01) concentrations which were associated with lower circulating NEFA (P<0.01) and BHBA (P<0.01) in CNT group than those of CON. The serum paraoxonase 1 (PON 1) activity and total antioxidant capacity (TAOC) were higher at -5 d in CNT than in CON (P<0.01, P=0.03; respectively). Close-up CNT improved lactose percentage and IgG concentration (P=0.03, P=0.04; respectively) and tended to improve percentage of protein and SNF (Solid Not Fat) in primary colostrum (P=0.06, respectively), without affecting colostrum fat and total solid (P=0.98, P=0.43; respectively). Supplementation of CNT in the diet during close-up period did not have adverse effects on metabolic profiles prepartum. Instead, this feeding regimen was more beneficial to antioxidant capacity and colostrum quality than feeding the control diet.

This study evaluated the effects of curcumin dietary supplementation on growth, physiology, carcass characteristics and meat quality in lambs. Thirty-two male Lacaune lambs (15.6 ± 0.63 kg, 60 ± 2.8 days of age) were randomly allocated in 16 pens (four treatments of four replicates with two lambs each) for 30 days. The animals were assigned to the following treatments: T0, T100, T200 and T300, representing 0, 100, 200 and 300 mg of curcumin/kg of concentrate, respectively. Curcumin dietary supplementation increased (P = 0.02) weight gain; on regression analysis, 315.1 mg curcumin/kg of concentrate was the dosage that provided the greatest weight gain. T200 and T300 lambs had lower (P = 0.04) erythrocytes numbers; T100 and T300 lambs had lower (P = 0.01) leukocyte numbers and T300 lambs had lower (P = 0.04) lymphocyte numbers, compared to T0 lambs. Globulin levels were significantly greater in the T200 group (P = 0.04) only on day 15 but not day 30; levels of total protein were significantly higher (P = 0.01) only in T200 and T300 group on day 15 and only in T200 group on d 30. Gamma-glutamyltransferase concentrations tended to be lower (P = 0.08) in T100, T200 and T300 group on d 15, and only in the T100 group on d 30. Curcumin dietary supplementation increased (P = 0.01) the serum activity of antioxidant enzymes and reduced (P = 0.01) levels of reactive oxygen species. In meat samples, T200 and T300 had greater total antioxidant capacity (P = 0.03) and lower (P = 0.01) lipoperoxidation rates. In carcasses, T300 lambs had greater (P ≤ 0.02) cooling weight losses and yields than did T0 lambs. Curcumin dietary supplementation also reduced (P ≤ 0.03) redness and yellowness. T200 and T300 lambs had fewer (P = 0.01) cooking losses and T200 lambs had greater (P = 0.03) water holding capacity than did T0 lambs. These findings suggest that curcumin dietary supplementation improves growth and antioxidant responses, as well as influencing meat quality in lambs.

Pectinase hydrolyses pectin and increases the utilization of agriculture byproducts as feeds for ruminants. A newly developed pectinase from Aspergillus terreus was compared with a commercially available pectinase at 600 IU/kg feed on feed utilization and lactational performance of Damascus goat fed orange pulp and sugar beet pulp based diet (i.e., pectin-rich diet) for 12 weeks. Thirty (one week postpartum) Damascus goats stratified by previous milk production, body weight and parity were divided into three experimental groups. Does were fed a basal diet containing concentrates, orange silage, sugar beet pulp and wheat straw at 50:20:20:10, respectively without a supplement (control treatment) or supplemented with a newly developed pectinase (New treatment) or commercial pectinase (Commercial treatment). With similar (P>0.05) feed intake, the new pectinase increased (P<0.01) nutrient digestibility and milk production efficiency more than the other treatments. Out of all the blood parameters, only serum glucose was affected by the treatments with highest (P=0.025) value noted for the new pectinase. Similarly, the new pectinase increased daily milk production (P<0.005) and the concentrations of milk components compared to the other two treatments. Additionally, pectinase (both the commercial and new) inclusion increased (P<0.05) the concentrations of total conjugated linoleic acid and unsaturated/saturated fatty acids ratio, and decreased atherogenic index (P=0.01) compared with control treatment. It is concluded that the supplementation of the diet of lactating goats with pectinase at 600 IU/kg feed will enhance feed digestion and milk production. The newly developed pectinase performed better than the commercial pectinase.

The present experiment evaluated the inclusion of chelated phytogenic feed additives mixture in the diet of lactating cows for the first 3 months of lactation. A week before calving, thirty multiparous Friesian cows were divided into three treatments in a complete randomized design and fed a basal diet without supplementation (Control treatment), or the control diet supplemented with chelated phytogenic additives at 3 g (PHY3 treatment), or at 6 g/cow/d (PHY6 treatment). Menthol, levomenthol, β-linaloolm, anethole, hexadecanoic acid and pmenthane were the principal compounds identified in the additives mixture. Milk production, total solid, protein, fat, and lactose were increased with PHY3, but decreased by PHY6 (P<0.01). Whereas the PHY3 treatment increased (P<0.05) milk contents of Ca and Zn, PHY3 and PHY6 treatments increased (P<0.05) milk Fe and Mn concentrations. Though the PHY3 treatment increased (P<0.05) nutrient digestibility, the PHY6 treatment decreased (P<0.05) the digestibility of organic matter, crude protein and neutral detergent fiber. The PHY3 treatment increased (P<0.05) ruminal volatile fatty acids (VFA) concentration and proportional acetate and propionate and decreased butyrate, while the PHY6 treatment decreased ruminal VFA concentration and proportional acetate. The PHY3 treatment increased (P<0.05) serum total protein, glucose, total antioxidant capacity, and the concentrations of Ca and Zn. Both PHY3 and PHY6 treatment decreased (P<0.05) the concentrations of serum triglycerides, and cholesterol. Daily inclusion of 3 g/cow of chelated feed additives mixture in diet of lactating cows improved milk production and ruminal fermentation, but additives dose of 6 g/cow/d had negative impact on cows’ performance.

The aim of this study was to determine whether dietary supplementation with zinc oxide nanoparticales (NP-ZnO) as a substitute for the conventional ZnO affects the intestinal digestibility of selected minerals, growth performance and meat quality in turkeys. The replacement of ZnO with NP-ZnO had no effect on the intestinal digestibility of Zn, Cu, Fe and Ca, whereas the lowest dose of supplemental Zn reduced Zn digestibility. The applied inclusion levels and sources of Zn had no effect on the growth performance (except the feed intake) of turkeys, including liveability. No differences in the relative weights of the heart, spleen and bursa of Fabricius (except the liver), or the weights of the femur and tibia were found between the dietary treatments. Neither the dose nor the source of supplemental Zn influenced carcass dressing percentage or the share of breast, thigh and drumstick muscles in the carcass. In comparison with the highest and moderate doses of Zn, the lowest inclusion level of Zn contributed to increased yellowness of breast meat (P=0.005). The analyzed doses and sources of supplemental Zn exerted varied effects on the redox status of fresh and frozen breast meat. In conclusion, the growth performance of turkeys, carcass yield and composition as well as the redox status of fresh and frozen breast meat were generally similar, regardless of the dietary source and level of Zn. The beneficial effect of Zn addition at 100 mg/kg was improved Zn and Ca digestibility, and increased redness of breast meat.

The aim of this study was to compare the quality of clutches and reproduction results of two groups of Roman snails (Helix pomatia) from the same local population, laying eggs simultaneously in semi-natural farm conditions and in a natural habitat. The study material were Roman snails aged 2 or more years which had entered the third phenological season of their life and thus the first season of sexual maturity. Observations were conducted at an earthen enclosure in a greenhouse belonging to the experimental farm for edible snails at the National Research Institute of Animal Reproduction in Balice near Kraków (Poland) as well as at a site where a local population naturally occurs in the uncultivated park surrounding the Radziwiłł Palace. In the June-July season, differences among such parameters as weight of clutch, number of eggs in clutch, mean egg weight, and hatchling percentage when compared to the total number of eggs in the clutch were compared. It was determined that clutches of eggs from the natural population laid in the greenhouse were of lesser weight (P<0.01), contained fewer eggs (P<0.05), and the mean weight of individual eggs was less (P<0.05) than in clutches laid simultaneously in a natural habitat. Both in the greenhouse and the natural habitat, in the first phase of laying eggs (June) the weight of the clutch and number of eggs its contained were greater than in the second phase (July). However, only for snails laying eggs in the greenhouse were these differences statistically significant (P<0.05) and highly significant (P<0.01), respectively. Statistically significant differences were not observed in hatchling percentage between eggs laid in the greenhouse and the natural habitat. The lower number of eggs laid in the farmed conditions of the greenhouse was successfully compensated for by the absence of mass destruction by rodents which occurred in the natural habitat.

The aim of the present study was to evaluate the changes in selected production and functional traits of Polish Holstein-Friesian cows after switching from a conventional (CMS) to an automatic milking system (AMS). The study consisted of 3398 Polish Holstein- Friesian dairy cows, from 16 herds in which CMS was changed to AMS. Cows were in their 1^st (L1) or 2^nd lactation (L2). The data consisted of milk yield [MY, kg], fat content [FC, %], protein content [PC, %], dry matter [DM, %], lactose content [LC, %], urea content [MU, mg/l], somatic cell count [SCC, thous./ml] and score [SCS, log]. The milking system had a significant impact on milk yield, fat, lactose, dry matter and urea contents. Regardless of lactation number, milk derived from CMS was characterised by higher values for FC, PC, DM SCC and SCS, while milk from AMS had higher MY, LC and MU. Multifactor analysis of variance also confirmed significant effect of herd, season, herd × milking system interaction on SCS in milk of cows in L1. In the studied herds change from CMS to AMS was evaluated separately for cows in L1 and L2. The transitioning from CMS to AMS resulted in the decrease of fat content in 6 L1 and 7 L2 herds, dry matter in 8 L1 and 5 L2 herds. SCS in milk also decreased in 4 L1 and 5 L2 herds. The change caused the increase of MY in 11 L1 and 9 L2 herds, lactose content in 6 L1 and 4 L2 herds and urea content in 9 L1 and 10 L2 herds. AMS may positively affect milk yield and health status, however, the change of milking system should be also accompanied by the change in herd management.

The present study aims to analyze the prevalence of E. coli O157 detected in foods of animal origin by meta-analysis. The prevalence of E. coli O157 detected in the different studies was combined to provide a common prevalence estimate, and heterogeneities between studies were investigated. The study material consisted of 49 studies investigating E. coli O157 prevalence in a total of 9600 food samples, including milk and dairy products, red meat and products, poultry meat and products, and cold appetizers between the years 1997-2019 in Turkey. In the meta-analysis, the Der-Simonian-Laird method was used. Meta-analyses were performed using the R 3.6.1. As a result of the meta-analysis, the common prevalence of E. coli O157 was 0.024 (0.018-0.029). As a result of the Egger’s Linear Regression Test, the study samples were found to be biased (t-value=6.092, P<0.001). To determine the source of heterogeneity between studies, sub-group and meta-regression analyses were performed in milk and dairy products, red meat and products, poultry meat and products, and ready-to-eat foods (RTEs). Accordingly, the prevalence of E. coli O157 in milk and dairy products, red meat and products, poultry meat and products, and RTEs was determined as 0.017, 0.031, 0.023, and 0.080 in Turkey, respectively. This study provides a stronger and more accurate estimation of the prevalence of E. coli O157 in foods of animal origin with the meta-analysis by eliminating inconsistencies in the effect of the sampling size of independent prevalence studies. However, in order to obtain accurate prevalence results in practice, it is necessary carefully to select the studies to be included in the analysis, to use the appropriate statistical model, and to interpret the results of the analysis correctly.