A new study published in the journal Small Ruminant Research found that feeding rams hemp seeds and hemp cake improved several measures of sperm quality, including membrane integrity, mitochondrial function and antioxidant status.
The research was conducted by researchers from the University of Warmia and Mazury in Olsztyn and the Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences.
For the study, the tea, examined 24 clinically healthy Polish Lowland ram lambs, dividing them into four groups receiving diets with different amounts and combinations of hemp-derived products. The diets were formulated to contain equivalent amounts of protein, allowing researchers to more specifically examine the effects of hemp seeds and hemp cake rather than differences in overall protein intake.
Hemp supplementation did not significantly change total sperm motility or most measures of sperm velocity. However, the hemp-fed groups showed significant improvements in plasma membrane integrity and mitochondrial membrane potential, two measures associated with sperm functionality and viability.
Researchers also observed changes in the balance between oxidative stress and antioxidant defenses. Glutathione peroxidase activity and total antioxidant status increased among the experimental groups, while total oxidant status and the oxidative stress index declined.
The strongest reduction in oxidative stress was observed among rams fed a 50:50 combination of hemp cake and hemp seeds.
One hemp treatment consisting of soybean meal and hemp seeds at a 50:50 ratio also produced significantly greater sperm straightness, while progressive motility showed a trend toward improvement.
The findings were not uniformly positive. Rams receiving the 50:50 hemp cake and hemp seed combination also had higher concentrations of malondialdehyde, a marker of lipid peroxidation. Researchers said this suggests that high inclusion levels of hemp ingredients may increase susceptibility to oxidative damage despite improvements in other antioxidant measures.
Industrial hemp seeds and hemp cake contain polyunsaturated fatty acids, including omega-3 and omega-6 fatty acids, as well as phenolic compounds and tocopherols that may affect cell membranes and oxidative balance.
The researchers concluded that appropriately formulated hemp-based diets can support sperm membrane function and antioxidant balance without negatively affecting motility.
However, they said the apparent increase in lipid peroxidation at higher inclusion levels points to a potentially dose-dependent effect and warrants additional research into the long-term reproductive effects of hemp-based livestock feed.
The researchers said this is the first study to evaluate hemp seed and hemp cake supplementation in relation to epididymal sperm quality, oxidative-antioxidative balance and plasma testosterone concentrations in rams.
