Assessment of the in-vitro probiotic efficacy and safety of Pediococcus pentosaceus L1 and Streptococcus thermophilus L3 isolated from Laban, a popular fermented milk product.

Probiotics are beneficial microorganisms, mostly lactic acid bacteria (LAB), that offer health benefits to the host when consumed in adequate amounts. This study assessed the probiotic efficacy and safety of LAB strains isolated from Laban, a traditional fermented milk product. Seven primarily selected Gram-positive, catalase-negative, non-spore-forming isolates were examined for their antimicrobial activity against the bacterial pathogens Bacillus cereus, Salmonella typhi, Staphylococcus aureus, and Vibrio cholera, and the fungal pathogen Candida albicans. Two isolates, identified as Pediococcus pentosaceus L1 and Streptococcus thermophilus L3, which showed antimicrobial activity against all pathogens, were further evaluated for their probiotic competence. The selected isolates demonstrated strong resistance to low pH, bile salts, and phenol, indicating their potential for gastric endurance. They also exhibited high cell surface hydrophobicity to various hydrocarbons, autoaggregation, and coaggregation properties, demonstrating strong adhesion abilities. In addition, both isolates showed strong antioxidant activity and were non-hemolytic. Although the isolates had some resistance to certain antibiotics, they were generally susceptible to commonly used antibiotics. The two LAB strains also exhibited promising technological properties, such as milk coagulation and exopolysaccharide production, indicating their potential to enhance the quality of dairy products. The results suggest that the LAB strains isolated from Laban have strong potential as probiotics, and due to their food origin, they are highly likely to exhibit maximal efficacy in food and pharmaceutical products for human consumption.

Growth performance, meat yield, oxidative stability, and Fatty Acid composition of meat from broilers fed diets supplemented with a medicinal plant and probiotics.

The experiment was carried out to investigate the effects of Alisma canaliculatum with probiotics (ACP) on the growth performance, meat composition, oxidative stability, and fatty acid composition of broiler meat. Sixteen probiotic strains were tested for their levels of acid, bile, and heat tolerance. Among them, Lactobacillus acidophilus KCTC 3111, Enterococcus faecium KCTC 2022, Bacillus subtilis KCTC 3239, and Saccharomyces cerevisiae KCTC 7928 were selected for use in ACP. Exactly 140 Ross broiler chicks were assigned to four dietary treatments in five replications for 5 wks in a completely randomized design. The dietary treatments were NC (Negative control; basal diet), PC (Positive control; basal diet with 0.005% Chlortetracycline), ACP-0.5% (basal diet with 0.5% ACP powder), and ACP-1% (basal diet with 1% ACP powder). According to the results, body weight of the broilers increased, and feed conversion ratio improved in the ACP-0.5% group compared to the NC group (p<0.05). Crude protein content of breast meat was higher (p<0.05) in the ACP-0.5% group, whereas crude fat content of thigh meat was lower (p<0.05) in the supplemented groups. Breast meat absolute and relative weights were both higher (p<0.05) in the ACP groups compared to the control group. Further, ACP diets increased gizzard and decreased large intestine relative weights, whereas kidney relative weight decreased upon the addition of a higher level (1%) of ACP (p<0.05). Thiobarbituric acid reactive substances values of breast and thigh meats were reduced (p<0.05) by ACP supplementation compared to control. Regarding the fatty acid composition of breast meat, arachidonic acid, docosahexaenoic acid, PUFA, and n6 fatty acid levels decreased (p<0.05) in the ACP groups, whereas the levels of linoleic acid, PUFA, PUFA/SFA, and n6 fatty acid in thigh meat decreased (p<0.05) by ACP and PC diets. It can be suggested based on the study results that ACP-0.5% diet could be an effective feed additive for broilers.

Plastic Film Mulching Improved Maize Yield, Water Use Efficiency, and N Use Efficiency under Dryland Farming System in Northeast China.

This 2-year field study analyzed plastic film mulching (PFM) effects on nitrogen use efficiency (NUE), and soil N pools under rainfed dryland conditions. Compared to no-mulching (NM, control), maize yields under PFM were increased by 36.3% (2515.7 kg ha−1) and 23.9% (1656.1 kg ha−1) in the 2020 and 2021 growing seasons, respectively. The PFM improved (p < 0.01) the water use efficiency (WUE) of maize by 39.6% and 33.8% in the 2020 and 2021 growing seasons, respectively. The 2-year average NUE of maize under the PFM was 40.1, which was 30.1% greater than the NM. The average soil total N, particulate organic N, and microbial biomass N contents under the PFM soil profile were increased by 22.3%, 51.9%, and 35%, respectively, over the two growing seasons. The residual 15N content (%TN) in soil total N pool was significantly higher (p < 0.05) under the PFM treatment. Our results suggest that PFM could increase maize productivity and sustainability of rainfed dryland faming systems by improving WUE, NUE, and soil N pools.

Effects of Plastic Film Mulching on Soil Enzyme Activities and Stoichiometry in Dryland Agroecosystems.

Soil extracellular enzymes are pivotal for microbial nutrient cycling in the ecosystem. In order to study the effects of different nitrogen application rates under plastic film mulching on soil extracellular enzyme activities and stoichiometry, five nitrogen application levels (i.e., 0, 90, 150, 225 and 300 kg·hm-2) were set based on two treatments: plastic film mulching (PM) and no film mulching (LD). We measured the soil extracellular enzyme activities (EEAs) and stoichiometry (EES) of four enzymes (i.e., ß-1,4-glucosidase (ßG), leucine aminopeptidase (LAP), ß-1,4-N-acetylaminoglucosidase (NAG) and alkaline phosphatase (AP)) involved in the C, N and P cycles of soil microorganisms in surface soil at five maize growth stages (seedling stage, jointing stage, trumpet stage, grout stage and harvest stage). The results showed that there were significant differences in soil EEA at different maize growth stages. The soil nutrient content and soil EEA were significantly improved under PM, and the stoichiometric ratio of extracellular enzymes (EC:N:P) was closer to 1:1:1, which indicated that PM was beneficial to the balance of soil nutrients and the activity of microorganisms. At each stage, with the increase in nitrogen application levels, the soil EEA showed a trend of increasing first and then decreasing (or remained unchanged), and both LD and PM treatments reached their highest activity at the 225 kg·hm-2 nitrogen application rate. When the nitrogen application level was less than 225 kg·hm-2, the soil enzyme activity was mainly limited by the N nutrient, and when the nitrogen application level reached 300 kg·hm-2, it was mainly limited by the P nutrient. RDA and correlation analysis showed that the soil C:P, C:N, N:P and pH had significant effects on soil ßG, NAG + LAP and AP activities as well as EC:N, EC:P and EN:P.

Substitution of Chemical Fertilizer with Organic Fertilizer Affects Soil Total Nitrogen and Its Fractions in Northern China.

The impact of chemical to organic fertilizer substitution on soil labile organic and stabilized N pools under intensive farming systems is unclear. Therefore, we analyzed the distribution of soil total N (STN), particulate organic N (PON), microbial biomass N (MBN), dissolved organic N (DON), and mineral N (NO3- and NH4+) levels down to 100 cm profile under wheat-maize rotation system in northern China. The experiment was established with four 270 kg ha-1 N equivalent fertilizer treatments: Organic manure (OM); Organic manure with nitrogen fertilizer (OM + NF); Nitrogen fertilizer (NF); and Control (CK). Results found that the OM and OM + NF treatments had significantly higher STN, PON, MBN, DON, and NO3- contents in 0-20 cm topsoil depths. Conversely, the NF treatment resulted in the highest (p < 0.01) DON and NO3- depositions in 40-100 cm subsoil depths. The NH4+ contents in selected profile depths were significantly highest (p < 0.01) under OM treatment. The correlations between STN and its fractions were positively significant at 0-10 and 10-20 cm topsoil depths. Our results suggest that partial substitution of chemical fertilizer with organic manure could be a sustainable option for soil N management of intensive farming systems.