In recent years, a boost in the ruminant population has been observed, and consequently, an increase in the animals’ demand for nutrients and methane emissions. Methane emission is generated during the microbial fermentation of feed in the rumen, and a percentage even up to 12% of the energy obtained by this process can be wasted. In addition, the use of antibiotics in animal husbandry is being increasingly restricted. restricted. As a result, there is a continuous search for innovative feed additives that can serve as alternatives to antibiotics, and will also be safe for both people and the environment. In the present review article, additives were selected on basis that, according to studies conducted so far, may positively affect the microbiome of the digestive system by improving indicators and/or reducing methane production. Among them, probiotics, prebiotics or their combination—synbiotics are at the forefront of research. However, additives in the form of algae or plant origin are also gaining ground in popularity, such as essential oils, fermented wheat straw or Gelidium amansii, due to their general recognition as safe (GRAS) for both humans and environment.

Studies carried out so far have indicated the effect of the microbiome on the composition of ruminant products. Recent studies have shown that not only diet, but also genetic factors can affect the microbiological composition of the digestive system. The aim of the study was to determine the differences in the levels of selected bacterial phyla in terms of breed differences. Three sheep breeds, i.e., Olkuska, Romanov, and old-type Polish Merino, differing in their use (meat–wool, meat, prolificacy) and country of breed origin were included in the study. Sheep at the same age and of the same sex were kept for a period of 3 months in the same environmental conditions and fed the same feed in the same proportions. The study included real-time PCR (polymerase chain reaction) analysis of feces collected before the slaughter and measurements of body weight and chilled carcasses. The obtained results showed significant differences between the breeds in the levels of bacterial populations tested. There were also differences in body weight between the breeds during the first weight measurements, however, the final results did not show any differences—after three months of maintenance all of them reached similar body weights, despite differences in fecal microbiological composition. The study suggests that in addition to diet and environmental conditions, the microbiology can also be influenced by breed.

The microbiome of animals, both in the digestive tract and in the skin, plays an important role in protecting the host. The skin is one of the largest surface organs for animals; therefore, the destabilization of the microbiota on its surface can increase the risk of diseases that may adversely affect animals’ health and production rates, including poultry. The aim of this study was to evaluate the effect of nutritional supplementation in the form of fermented rapeseed meal and housing conditions on the level of selected bacteria phyla (Firmicutes, Actinobacteria, and family Lactobacillaceae). The study was performed on 30 specimens of broiler chickens (Ross 308), individually kept in metabolic cages for 36 days. They were divided into 5 groups depending on the feed received. On day 36, skin swabs were individually collected. Temperature and humidity were measured in the room. The temperature was measured every 2 days (18 measurements × 6 points). The results of Real-Time PCR analysis have shown a significant effect of the feed additive on the level of Firmicutes phylum on the skin. On the other hand, a variable level of the tested bacteria was shown depending on the location of the cages. The Firmicutes phylum and Lactobacillaceae family achieved the highest level in the top-window zone. However, in the case of the Actinobacteria phylum, the highest level was found at the top-door and middle-door zones. The obtained results suggest that the conditions in which animals live may affect the microbiota of their skin.

European populations of the grey partridge (Perdix perdix L.) have declined rapidly, necessitating captive breeding programs to supplement wild populations. Artificial insemination could optimize these reproductive efforts, yet specific protocols are lacking. This study evaluated the effects of short-term liquid storage (24 h at 5 °C in EK and Lake extenders) on selected semen quality parameters and determined how extender type and sperm dose affects fertility level. Semen was collected from 15 males, pooled, diluted 1:2 and evaluated in vitro at 0 h and after 24 h of storage. Sperm motility and kinematics were assessed using Sperm Class Analysis system, whereas viability and morphology were evaluated by nigrosin-eosin staining. Obtained data was analyzed using repeated measures ANOVA. Fertilization outcomes, assessed by incubating eggs laid following artificial insemination, were analyzed using generalized linear mixed models. Storage significantly reduced sperm motility, viability and the proportion of morphologically normal spermatozoa (P < 0.05). The EK extender better preserved sperm viability and normal morphology, whereas the Lake extender maintained a more stable kinetic profile over the time. Fresh ejaculates naturally exhibited a remarkably low proportion of morphologically normal spermatozoa (14.2%). In vivo, sperm dose significantly affected fertilization success (P < 0.05); with higher doses (≥ 16 × 10⁶ spermatozoa) consistently resulting in higher fertility rates in both fresh and stored semen. Extender type did not significantly affect fertilization rates. Progressive motility showed a tendency to predict fertilization success after storage (P = 0.06). Despite reduced in vitro semen quality, short-term liquid storage of grey partridge semen can be effectively applied in artificial insemination procedures when an adequate sperm dose is used. These findings provide a practical basis for improving reproductive management and developing genetic resource conservation strategies in this species.

The European population of the grey partridge (Perdix perdix L.) in the natural environment is rapidly declining. The aim of the present study was to determine the feasibility of fertilization using cryopreserved semen. The study was conducted on one-year-old birds: ten males and four females. Semen was frozen using a modified method developed for capercaillie semen. Eight artificial inseminations were performed with cryopreserved semen, with each female inseminated twice, using a mean dose of 6.1 × 10⁶ live spermatozoa. The mean fertilization rate was 25.0%, and the duration of fertility after a single insemination was two days. The results demonstrated the possibility of using cryopreserved semen in the reproduction of the grey partridge, which may be helpful for the future conservation of this species.