Biotechnology Journal International

Genetic and Non-genetic Factors Affecting Heat Production in Farm Animals

Muslim Kayode Ewuola — 2026-07-13

Farm animals produce heat through a complex biological process that is influenced by their environment, genetics, metabolism, nutrition, and management. Heat stress is a condition that imposes quantifiable consequences on productivity, reproduction, immunological function, and animal welfare across all major livestock species when heat output exceeds dissipation capability. This review examines the biological and environmental factors influencing heat production and heat stress in major farm animal species, including dairy and beef cattle, swine, poultry, water buffalo, sheep, goats, camels, horses, and rabbits. The present review was conducted using secondary sources derived from existing academic literature, including peer-reviewed journal articles, books, and conference proceedings. Each species has distinct vulnerabilities. The fleece that provides sheep with resistance to cold weather also traps metabolic heat in warm weather, a phenomenon known as the "fleece insulation paradox." Although goats have a more flexible thermoregulatory system, prolonged exposure to high humidity can still pose a serious threat to their health. Camels' exceptional heterothermic traits distinguish them from other domestic ruminants. Horses rely primarily on sweat-based cooling at rates that rapidly deplete electrolytes, and they produce exercise-induced heat loads surpassing 1,000 W, an intensity unmatched by other domestic species. With their thin insulating coat, lack of functional sweat glands, and dependence on panting, which becomes ineffective above 28–30°C, rabbits are possibly the most thermally sensitive commonly farmed animal. This review critically evaluates evidence-based mitigation strategies across all ten species, including nutritional interventions, cooling technologies, genetic selection approaches, and real-time monitoring systems, with attention to the diversity of production environments in which these strategies can be applied.

Joint Effects of Water-Miscible Solvents on Kluyveromyces marxianus Cell-Free β-Galactosidase Activity

Oluchukwu Roseline Nweke — 2026-07-08

Aim: The study aims to assess the inhibitory effects of ethanol-N,N-dimethylformamide (DMF) and ethanol-dimethyl sulfoxide (DMSO) binary mixtures on Kluyveromyces marxianus cell-free β-galactosidase activity.

Study design: A cell-free enzyme assay integrating concentration-response modelling with mixture-toxicity analysis was used to characterize the inhibitory effects of ethanol, DMSO, DMF and their binary mixtures on Kluyveromyces marxianus β-galactosidase activity.

Methods: No-observable-effect concentration (NOEC) and median inhibitory concentration (EC₅₀) limits were calculated by fitting concentration-response relationships for the individual solvents and mixtures to a Gompertz model. Values generated from the prediction models are presented as mean ± standard deviation. One-way analysis of variance (ANOVA), followed by Duncan's post hoc test, was used to determine significant differences among treatments.

Results: The NOEC values for ethanol, DMSO and DMF were 2.651 ± 0.796%, 2.215 ± 0.309% and 0.920 ± 1.161%, respectively. The corresponding EC₅₀ values were 18.930 ± 1.171%, 19.114 ± 0.534% and 13.587 ± 0.489%, respectively, giving an inhibition order of DMF > DMSO ≥ ethanol. Ethanol-DMSO and ethanol-DMF mixtures with higher EC₅₀ and NOEC values showed lower inhibitory effects than the individual solvents, particularly DMF and DMSO. The toxic index (TI) and concentration addition (CA) model were used to predict the inhibitory effects of ethanol-DMF and ethanol-DMSO mixtures. The CA-predicted EC₅₀ values of ethanol-DMSO and ethanol-DMF mixtures ranged from 18.880 ± 1.444 to 18.897 ± 1.604 and from 18.525 ± 0.886 to 22.664 ± 1.099, respectively. TI values for ethanol-DMSO mixtures ranged from 1.018 ± 0.014 to 1.062 ± 0.021. Ethanol-DMF mixtures at ratios of 9:1 and 8:2 indicated synergistic effects, whereas ratios of 7:3 and 6:4 indicated additive effects. For TI values marginally above 1, the joint effect was adjudged additive because the observed EC₅₀ values were not significantly different from the CA-predicted EC₅₀ values.

Conclusion: This study provides foundational information for establishing sub-inhibitory concentrations of water-miscible solvents for the in situ β-galactosidase activity assay derived from Kluyveromyces marxianus.

Can Coir Pith-Starch-Plant Growth Promoting Rhizobacteria Composite Sustain Zea mays Seedling Survival and Growth under Flood (Waterlog) Condition?

Chinyere Augusta Ajuzieogu — 2026-07-10

Aim: This study was conducted to formulate and evaluate the efficacy of a composite: coir pith + starch + plant-growth-promoting rhizobacteria (PGPR), in sustaining the survival and growth of Zea mays (maize) seeds cultivated under flood stress.

Place and Duration of Study: Department of Microbiology Laboratory, Federal University Otuoke, Bayelsa State, Nigeria, between May and July 2024.

Methodology: Rhizobacteria were isolated, screened for plant-growth-promoting (PGP) traits; phosphate solubilisation and indole-3-acetic acid (IAA) production and further tested for PGP activity via seed germination bioassay. Composites were prepared by homogenizing coir pith, starch gel and standardized PGPR inoculum at a ratio of 2:24:20 (w/v), pelleted and dried at 28^oC. The efficacy of the composites was examined in a pot experiment by measuring shoot length (SL), root length (RL) and plant height (PH), of the treated maize seeds. Treatments were conducted in two sets (single composite pellet and 4 composite pellets); Set 1 (seeds + 1 composite pellet/pot, Control 1 and Control 2), Set 2 (seeds + 4 composite pellets/pot, Control 1 and Control 2). Controls 1 and 2 were; seeds + coir pith + starch only and maize seeds only, respectively. Set 1 was monitored for 2 weeks, and Set 2 for 7 days. Flood conditions were simulated by saturating the pots with water, without drainage, for 3 days.

Results: Five rhizobacteria were isolated; LCE tested positive for IAA production and phosphate solubilisation, SPP tested positive for IAA production only, and C tested positive for phosphate solubilization only. The growth performance of treated maize seeds under waterlogged condition in Set 1 indicated that the Control 1 (maize seeds + 1 coir pith + starch only pellet) was more effective than Control 2 and the other composites. The treatments in Set 1 did not support maize seed growth throughout the two-week monitoring period, except control 1 (maize seeds + 1 coir pith +starch only) which sustained seed survival and growth for 2 weeks. One way ANOVA indicated that the mean growth for control 1 was the same across the weeks as the p-value (p = 0.658) is greater than the 5% significance level (α = 0.05). In Set 2, at day 7, the observed survival and growth of maize seeds treated resulted from the application of 4 coir pith+starch+LCE (Priestia flexa) pellets. The mean SL, RL and PH recorded for the seeds were 2.6±0.2, 3.6±0.45 and 15.9±0.45 cm, respectively. LCE was identified by 16S rRNA sequencing as Priestia flexa.

Conclusion: This study demonstrates the potential of coir pith+ starch+Priestia flexa to mitigate waterlogging stress, sustain survival and growth of Zea mays seedlings.