Use of Natural Biomolecules in Animal Feed to Enhance Livestock Reproduction

Omar M.E., Hassanein E.M., Shehabeldin A.M., Szenci O., El-Shereif A.A.

Objectives: This study aimed to evaluate the effectiveness of gonadotropin-releasing hormone-loaded chitosan–TPP nanoparticles (GnRH-CNPs) and prostaglandin F2α-loaded chitosan–TPP nanoparticles (PGF2α-CNPs) within the Ovsynch protocol for enhancing reproductive performance in heat-stressed dairy cows. Methods: Thirty-six cyclic purebred Friesian cows not detected in standing heat for more than 90 days postpartum were randomly allocated to three treatment groups. The control group (OVS, n = 12) followed the standard Ovsynch protocol with conventional doses. The ½ OVS group (n = 12) received 5 µg GnRH-CNPs on days 0 and 9, along with 250 µg PGF2α-CNPs on day 7. While the ¼ OVS group (n = 12) was administered 2.5 µg GnRH-CNPs on days 0 and 9, with 125 µg PGF2α-CNPs on day 7. Ovarian follicular dynamics and corpus luteum (CL) development were monitored on days 0, 4, 7, and 9 of the protocol. Serum progesterone (P4) concentrations were measured throughout the synchronization period and on days 15 and 30 post-AI. Pregnancy was diagnosed on day 30 post-AI. Results: The ¼ OVS protocol achieved a significantly greater follicular response (p < 0.05) than other protocols. On day 4, following the first GnRH administration, the OVS group exhibited a higher number of subordinate follicles (p < 0.05) and a greater diameter of the dominant follicles (DFs), whereas the ¼ OVS group showed a greater subordinate follicle diameter (p < 0.05) and a higher number of DFs. On day 9, after PGF2α administration, the ¼ OVS group maintained an elevated number of subordinate follicles, while larger subordinate follicle diameters were observed in the ½ OVS and OVS groups. No significant differences in DF numbers and diameters were observed among groups. P4 concentrations remained similar across groups during treatments. Compared to control, a significantly higher value of P4 concentration (p < 0.05) was recorded on day 15 post-AI in the ½ OVS group and on day 30 post-AI in the ¼ OVS group. These findings correlated with a higher pregnancy rate in the ¼ OVS group (65%) compared to the ½ OVS and OVS groups (40% in each). Conclusions: Nanofabrication reduced GnRH and PGF2α dosage by 50% and 75% without impairing ovarian response and pregnancy rates. The ¼ OVS protocol notably enhanced the ovarian activity and fertility, highlighting the use of GnRH-CNPs and PGF2α-CNPs as promising and practical approaches to enhance the fertility in dairy cattle under heat stress (HS).

Oladejo E.O., Gruhot T.R., Park S., Ishak G.M., Mote B.E., Liao S.F., Feugang J.M.

This study investigated the impact of an increased arginine (ARG) level in a boar diet on semen production, sperm quality, and seminal plasma proteome. Adult Nebraska Index Line boars were assigned to two groups, one receiving a control diet with 0.77% arginine (n = 4) and the other a high-arginine diet with 1.77% arginine (n = 5). Semen was collected twice a week over the whole experiment, including one week before, six weeks during, and six weeks after the supplementation. Parameters such as semen volume and concentration were assessed immediately after collection, alongside sperm motility and morphology. Centrifugation of raw semen samples yielded seminal plasma for a gel-based proteome analysis. The seminal plasma proteins were extracted, quantified, and separated via 2D gel electrophoresis, allowing protein identification through mass spectrometry. Data analysis involved two-way ANOVA for comparisons (p < 0.05). Results showed that arginine supplementation improved semen volume and total sperm counts, with averages of 21 ± 3 doses in the control group versus 24 ± 2 in the ARG group (p = 0.05). Although sperm motility and morphology remained unaffected (p > 0.05), dietary arginine upregulated ten proteins and downregulated two. In summary, increased dietary arginine did not significantly alter key parameters of semen output or sperm quality but significantly impacted seminal plasma proteome, warranting further research on sperm viability.

Kujoana T.C., Sehlabela L.D., Mabelebele M., Sebola N.A.

Male reproductive efficiency is primarily defined by the generation of high-quality and viable sperm cells in farm animals. However, the literature shows that male fertility has declined in recent years due various factors including heat stress, which causes the development of free radicals and reactive oxygen species (ROS) which damages sperm cells. This review aimed to examine the potential significance of antioxidants in increasing and preserving sperm quality and viability. Data used to produce this review paper came from recently published articles in peer reviewed journals. Google Scholar, Science Direct, Research Gate, Web of Science, and the Directory of Open Access Journals were used to access the data. Various studies have shown that antioxidants play acritical role in preserving the sperm quality and viability by protecting sperm cells from the potential damage from oxidative stress induced by the development of oxygen species imbalances. However, there is less information on the use of natural or synthetic antioxidants to preserve semen quality through in vivo procedures, despite its growing popularity and promising results. Hence, there is a need for researchers to explore more on this topic, especially in other livestock species than poultry.

Akhtar P., Rajoriya J.S., Singh A.K., Ojha B.K., Jha A.K., Bisen A., Bajaj N.K., Ahirwar M.K., Raje A., Singh A.P., Peepar S.S., Mishra A.K., Katiyar R., Chamuah J., Singh M.

The present study evaluated the effects of omega-3 (ω-3) fatty acid-rich linseed supplementation on the reproductive performance, endocrine profile, and biochemical profile of ewes reared in subtropical climates. Forty-eight acyclic and clinically healthy Marwari sheep, aged 1.5–2.5 years with no parity, were divided into four groups (n = n = 12 in each). Ewes in the control group (group I) were fed only a basal feed, whereas ewes in the treatment groups II, III, and IV were fed the basal diet along with 10%, 15%, and 20% linseed, respectively, daily on a dry matter basis. The experiment was conducted during the typical breeding season (October–November) of the sheep. The estrus induction rate was significantly higher (p &lt; 0.05) in all treatment groups than in the control group. The estrus induction interval was significantly lower (p &lt; 0.05) in group III. The conception rate in group I was significantly lower (p &lt; 0.05). In addition, ewes in the control group had a significantly lower (p &lt; 0.05) lambing rate than all treatment groups. Serum progesterone concentrations differed significantly (p &lt; 0.05) between the control and the treatment groups on days 15, 30, 45, and 60 of supplementation. On treatment days 15 and 30, the serum estrogen concentrations were significantly higher (p &lt; 0.05) in all treatment groups compared to that in group I. In all treatment groups, monounsaturated fatty acid (MUFA) decreased significantly (p &lt; 0.05), whereas polyunsaturated fatty acid (PUFA) increased significantly (p &lt; 0.05) from day 15 onward. In conclusion, by providing 15% dietary linseed supplementation to ewes, their reproductive performance can be improved in subtropical climates. Future studies are recommended to further elucidate the role of linseed supplementation in sheep reproduction in subtropical climates.

Gai Z., Hu S., He Y., Yan S., Wang R., Gong G., Zhao J.

As global warming intensifies, extreme heat is becoming increasingly frequent. These extreme heatwaves have decreased the milk production of dairy animals such as cows and goats and have caused significant damage to the entire dairy industry. It is known that heat stress (HS) can induce the apoptosis and autophagy of mammary epithelial cells (MECs), leading to a decrease in lactating MECs. L-arginine can effectively attenuate HS-induced decreases in milk yield, but the exact mechanisms are not fully understood. In this study, we found that HS upregulated the arginine sensor CASTOR1 in mouse MECs. Arginine activated mTORC1 activity through CASTOR1 and promoted mitochondrial biogenesis through the mTORC1/PGC-1α/NRF1 pathway. Moreover, arginine inhibited mitophagy through the CASTOR1/PINK1/Parkin pathway. Mitochondrial homeostasis ensures ATP synthesis and a stable cellular redox state for MECs under HS, further alleviating HS-induced damage and improving the lactation performance of MECs. In conclusion, these findings reveal the molecular mechanisms by which L-arginine relieves HS-induced mammary gland injury, and suggest that the intake of arginine-based feeds or feed additives is a promising method to increase the milk yield of dairy animals in extreme heat conditions.

Adnane M., Whiston R., Tasara T., Bleul U., Chapwanya A.

Uterine disease in cattle impairs reproductive performance and profitability and increases antibiotic use and antimicrobial resistance. Thus, probiotics offer a promising alternative therapy. This review presents conceptual findings on the efficacy of probiotics in managing uterine diseases and fertility in cows. Probiotics containing Lactobacillus spp. and Bifidobacterium spp. individually or as composite formulations are known to improve fertility. Strategic intravaginal administration of these formulations would likely enhance uterine immunity, particularly during the postpartum period. While current findings on the benefits to uterine health are encouraging, there is still significant knowledge missing, including a lack of empirical information from large-scale field trials. This review underscores the need for evidence-based guidelines for probiotics, such as genomic selection of formulations, targeted delivery, or potential synergy with other interventions. Future research should address these gaps to maximize the potential of probiotics in managing uterine diseases and enhancing the reproductive health of dairy cattle.

Li Y., Shi C., Deng J., Qiu X., Zhang S., Wang H., Qin X., He Y., Cao B., Su H.

Polyphenol-rich grape pomace (GP) represents a valuable processing by-product with considerable potential as sustainable livestock feed. This study aimed to investigate the effects of different levels of GP on the growth performance and nitrogen utilization efficiency, antioxidant activity, and rumen and rectum microbiota of Angus bulls. Thirty Angus bulls were allocated three dietary treatments according to a completely randomized design: 0% (G0), 10% (G10), and 20% (G20) corn silage dry matter replaced with dried GP dry matter. The results showed that the average daily gain (ADG) of the G0 group and G10 group was higher than that of the G20 group (p < 0.05); urinary nitrogen levels decreased linearly with the addition of GP (linear, p < 0.05). In terms of antioxidants, the levels of catalase (CAT) in the G10 group were higher than in the G0 and G20 groups (p < 0.05), and the total antioxidative capacity (T-AOC) was significantly higher than that in the G20 group (p < 0.05). In addition, in the analysis of a microbial network diagram, the G10 group had better microbial community complexity and stability. Overall, these findings offer valuable insights into the potential benefits of incorporating GP into the diet of ruminants.

Long Y., Paengkoum S., Lu S., Niu X., Thongpea S., Taethaisong N., Han Y., Paengkoum P.

Lycopene is a kind of natural carotenoid that could achieve antioxidant, anti-cancer, lipid-lowering and immune-improving effects by up-regulating or down-regulating genes related to antioxidant, anti-cancer, lipid-lowering and immunity. Furthermore, lycopene is natural, pollution-free, and has no toxic side effects. The application of lycopene in animal production has shown that it could improve livestock production performance, slaughter performance, immunity, antioxidant capacity, intestinal health, and meat quality. Therefore, lycopene as a new type of feed additive, has broader application prospects in many antibiotic-forbidden environments. This article serves as a reference for the use of lycopene as a health feed additive in animal production by going over its physical and chemical characteristics, antioxidant, lipid-lowering, anti-cancer, and application in animal production.

Omondi V.O., Bosire G.O., Onyari J.M., Kibet C., Mwasya S., Onyonyi V.N., Getahun M.N.

ABSTRACT Ruminant livestock, including cattle, sheep, goats, and camels, possess a distinctive digestive system with complex microbiota communities critical for feed conversion and secondary metabolite production, including greenhouse gases. Yet, there is limited knowledge regarding the diversity of rumen microbes and metabolites benefiting livestock physiology, productivity, climate impact, and defense mechanisms across ruminant species. In this study, we utilized metataxonomics and metabolomics data from four evolutionarily distinct livestock species, which had fed on diverse plant materials like grass, shrubs, and acacia trees, to uncover the unique signature microbes and secondary metabolites. We established the presence of a distinctive anaerobic fungus called Oontomyces in camels, while cattle exhibited a higher prevalence of unique microbes like Psychrobacter , Anaeromyces , Cyllamyces , and Orpinomyces . Goats hosted Cleistothelebolus , and Liebetanzomyces was unique to sheep. Furthermore, we identified a set of conserved core microbes, including Prevotella , Rickenellaceae , Cladosporium , and Pecoramyces, present in all the ruminants, irrespective of host genetics and dietary composition. This underscores their indispensable role in maintaining crucial physiological functions. Regarding secondary metabolites, camel’s rumen is rich in organic acids, goat’s rumen is rich in alcohols and hydrocarbons, sheep’s rumen is rich in indoles, and cattle’s rumen is rich in sesquiterpenes. Additionally, linalool propionate and terpinolene were uniquely found in sheep rumen, while valencene was exclusive to cattle. This may suggest the existence of species-specific microbes and metabolites that require host rumen-microbes’ environment balance. These results have implications for manipulating the rumen environment to target specific microbes and secondary metabolite networks, thereby enhancing livestock productivity, resilience, reducing susceptibility to vectors, and environmentally preferred livestock husbandry. IMPORTANCE Rumen fermentation, which depends on feed components and rumen microbes, plays a crucial role in feed conversion and the production of various metabolites important for the physiological functions, health, and environmental smartness of ruminant livestock, in addition to providing food for humans. However, given the complexity and variation of the rumen ecosystem and feed of these various livestock species, combined with inter-individual differences between gut microbial communities, how they influence the rumen secondary metabolites remains elusive. Using metagenomics and metabolomics approaches, we show that each livestock species has a signature microbe(s) and secondary metabolites. These findings may contribute toward understanding the rumen ecosystem, microbiome and metabolite networks, which may provide a gateway to manipulating rumen ecosystem pathways toward making livestock production efficient, sustainable, and environmentally friendly.

Keane J.A., Ealy A.D.

The in vitro production (IVP) of bovine embryos has gained popularity worldwide and in recent years and its use for producing embryos from genetically elite heifers and cows has surpassed the use of conventional superovulation-based embryo production schemes. There are, however, several issues with the IVP of embryos that remain unresolved. One limitation of special concern is the low efficiency of the IVP of embryos. Exposure to reactive oxygen species (ROS) is one reason why the production of embryos with IVP is diminished. These highly reactive molecules are generated in small amounts through normal cellular metabolism, but their abundances increase in embryo culture because of oocyte and embryo exposure to temperature fluctuations, light exposure, pH changes, atmospheric oxygen tension, suboptimal culture media formulations, and cryopreservation. When uncontrolled, ROS produce detrimental effects on the structure and function of genomic and mitochondrial DNA, alter DNA methylation, increase lipid membrane damage, and modify protein activity. Several intrinsic enzymatic pathways control ROS abundance and damage, and antioxidants react with and reduce the reactive potential of ROS. This review will focus on exploring the efficiency of supplementing several of these antioxidant molecules on oocyte maturation, sperm viability, fertilization, and embryo culture.

Sun S., Lv M., Niu H., Luo J.

In large-scale intensive farms, dairy goats often undergo frequent estrus synchronization (ES) treatment, which may result in a decline in reproductive performance; however, the underlying mechanism remains unclear. The present study aimed to investigate the effect of pregnant mare serum gonadotropin (PMSG) and progesterone (P4)-mediated ES treatment on fertility in dairy goats, while also identifying key metabolic and endocrine mechanisms that influence reproductive performance in does subjected to repeated ES treatment. Forty-eight Saanen does were randomly assigned to two groups (24 goats each) that received ES treatments either thrice fortnightly (3-PMSG) or once (1-PMSG) simultaneously with the third ES treatment of the 3-PMSG group during the breeding season. ES treatment was performed via the intravaginal insertion of a controlled internal drug release (CIDR) device impregnated with 300 mg P4, followed by 300 IU PMSG injections 48 h before CIDR withdrawal. Blood was collected to detect the level of hormones and blood biochemical indices. Additionally, estrus rate, fecundity rate, body weight, size, and lactation performance were measured. The results showed that repeated ES treatment markedly decreased the estrus rate and fecundity rate of goats. Among the does in all groups, there was no substantial difference in follicle stimulating hormone, luteinising hormone, gonadotropin-releasing hormone, melatonin, growth hormone, PMSG, total cholesterol, total protein, and glucose levels, as well as the body weight, body size, and lactation performance. Repeated ES treatment elevated estrogen (E2) levels 36, 48, and 72 h post-CIDR removal; increased P4 upon CIDR insertion; and raised PMSG antibody levels 24, 48, and 72 h post-CIDR removal. The results suggest that elevated anti-PMSG levels are the primary reason for the decline in ES efficiency, and that high E2 and P4 levels at some time points also impair reproductive performance. These findings provide novel insights into the metabolic effects of repeated PMSG stimulation in goats, guiding future reproductive hormone use in breeding practices.

Kujoana T.C., Mabelebele M., Sebola N.A.

Abstract Dietary fats serve a multitude of purposes in both humans and animals. They are a component of membranes and support the regulation of cellular influx and egress. They aid in the production of hormones, milk, embryonic, and foetal development, movement, and storage of energy, as well as absorption of fat-soluble vitamins. The objective of this review is to describe how dietary fats contribute to improved livestock reproductive performance. Data for this review study were acquired from recently published works in different journals. Databases were accessed using electronic data sources such as Google Scholar, PubMed, Science Direct, Research Gate, Web of Science, and the Directory of Open Access Journals. It is believed that dietary fats added to animal diets enhance animal reproduction by boosting the quantity and size of ovarian follicles and concentration of hormone progesterone plasma, declining the production of prostaglandin metabolites and increasing the lifespan of corpus luteum, which is also crucial for semen maturation, motility, and acrosomal reactions in addition to reproductive hormones. Therefore, it is important to employ dietary fats effectively to boost livestock reproduction and maximise animal output, which will achieve the relevant Sustainable Development Goals and food security.

Pascal C., Nechifor I., Florea M.A., Pânzaru C., Simeanu D., Mierliță D.

This study aims to analyze the influence of an improved diet with vitamins and minerals (VM) on the live weight, body condition, quality of sperm, behavior, and fertility of rams. The biological material comprised two groups of rams (L1—control and L2—VM supplemented), each consisting of 15 individuals. After a complete one-year cycle, they received different dietary treatments at the beginning of the preparation for the reproduction period. Although in the onset of the mounting period (SM), no significant differences were observed for live weight (p > 0.05), providing supplemental feeding of a VM complex allowed a better capitalization of body reserves, and, consequently, the rams’ groups differed significantly by the end of mating season (FM), for live weight (+4.1%; p < 0.001) and body condition score (+15.9%; p < 0.05). Adding vitamins and minerals to the L2 diet also improved sperm color (p < 0.001), sperm concentration (+11.8%; p < 0.01), live spermatozoa (+2.6%; p < 0.001), and decreased abnormal spermatozoa proportion (−7.0%; p < 0.01). The increase in the scrotum circumference in L2 (+4.57%) suggests that VM supplements improved testosterone secretion, spermatogenesis, and ejaculate volume (+10.20%; (p < 0.001), with a positive impact (p < 0.001) on mating behavior, on the gestation installation (+11.2%) and on the number of obtained lambs (+14.0%), as well as on the key economic indicators (+13.8% incomes per ram).

Abebe A., Berhane G., Getachew T., Gizaw S., Haile A.

This study evaluated the reproductive and productivity of local and Dorper crossbred ewes in a community-based management system. We analyzed data collected from 2013 to 2021, taking into account different factors such as dam-breed, location, type of birth, season, and year of lambing. Lambing was observed all year-round, but the majority (35%) occurred in September, October, and December. This suggests that pasture availability, which is influenced by climatic-factors, may play a role in the seasonality of lambing. Litter-size at birth and weaning did not show any significant difference. Age at first lambing varied between breeds (P < 0.001), while lambing-interval and annual reproductive rates were unaffected by dam-breed (P > 0.05). The annual number of lambing per year significantly varied based on location and lambing seasons (P < 0.001), with a higher frequency during the major rainy-season compared to the dry-season (1.58vs1.42), highlighting the influence of feed availability. Productivity indices of ewes were calculated. Location and season of lambing had a significant impact on annual ewe productivity, while the ewe genotype showed no significant influence on productivity indices, except for the weight of lambs produced per kilogram of metabolic weight (0.84vs0.72 lambs per kg ewe and year; P < 0.01: 2.02vs1.77 kg lamb per kg0.75 ewe and year), where local ewes outperformed Dorper crossbred ewes. The difference in annual-productivity indices between local and Dorper crossbred ewes was more evident when considering the postpartum weight, as the ewes exhibited higher postpartum weights. However, both ewe genotypes produced comparable lamb weights per year (20.91vs20.16 kg lamb weaned per ewe and year for local and Dorper crossbred ewes, respectively). In summary, under low-input conditions, Dorper crossbred ewes demonstrated comparable reproductive performances and productivity traits to local ewes. Nevertheless, breed and environmental factors identified in this study should be taken into account to enhance sheep productivity in both local and Dorper crossbred ewes.

Bó G.A., Menchaca A.