Scientists from University College Dublin report that laminarin, a storage glucan found in brown algae, was associated with increases in daily gain and gain:feed ratio, compared to a control diet.
Writing in the British Journal of Nutrition the UCD scientists note that the effects were similar to zinc oxide, making it a potential alternative to ZnO supplementation in weaned pigs.
On the flip side, combining with fucoidan, another seaweed-derived compound, did not enhance the results, they said.
With or without ZnO?
The researchers explain that, while laminarin and fucoidan have shown promise as a supplement for weaned piglets, their bioactivity in the presence of additives such as ZnO will dictate who successfully they can be applied in pig nutrition.
Another paper published in the British Journal of Nutrition tested the effects of seaweed extracts rich in laminarin and fucoidan with without ZnO on the growth of weaned pigs.
Data from 192 animals indicated that the diets supplemented with either seaweed extract or ZnO resulted in feed conversion efficiency improvements, but any such improvements disappeared when the additives were used together.
Moreover, the diet containing only seaweed extract improved the piglets digestibility of organic matter, and this effect was not observed when combined with ZnO.
“Seaweed extract and ZnO improve growth performance when given alone, but not when given in combination,” they wrote. “The biological effect of seaweed extract on selected digestibility and faecal characteristics was markedly different when compared with that of ZnO.”
Immune health
The Irish data indicates that laminarin may offer the greatest benefits, compared to fucoidan. A study in Animal Feed Science and Technology (Vol. 183, pp. 151-159) indicated that laminarin inclusion in the diet at a level of 300 mg/kg produced the greatest results in terms of growth performance with improvements in average daily gain and gain:feed ratio. Combining this with fucoidan had limited additional effects, they said.
In an attempt to elucidate the potential mechanism, the researchers investigated how the seaweed extracts would affect intestinal morphology, gut microbiota, and inflammatory cytokines. Results published in the British Journal of Nutrition indicated that fucoidan reduced the population of Enterobacteriaceae population, compared with pigs being fed a control diet.
Laminarin was associated with a reduction in the abundance of effacing Escherichia coli strains. These benefits were not observed when the two seaweed-derived compounds were combined, however.
The extracts were found to affect intestinal morphology when provided independently of each other, but no such effects were observed when combined.
In a blog post on pig333.com, lead researcher John O'Doherty stated: “Overall, the reductions in E.coli populations and the increase in daily gain and gain to feed ratio suggest that sea weed extracts may provide a dietary means to improve gut health post weaning. However, the effects of seaweed extracts on piglet performance depends on the extraction process and the variety of seaweeds used.”
Sources:
Volume 111, Number 9, Pages 1577-1585. doi: 10.1017/S0007114513004224
“Effect of seaweed-derived laminarin and fucoidan and zinc oxide on gut morphology, nutrient transporters, nutrient digestibility, growth performance and selected microbial populations in weaned pigs”
Authors: G. Heim, A.M. Walsh, T. Sweeney, D.N. Doyle, C.J. O'Shea, M.T. Ryan, J.V. O'Doherty
Volume 110, Issue 09, Pages 1630-1638, doi: 10.1017/S0007114513000834
“Effect of dietary laminarin and fucoidan on selected microbiota, intestinal morphology and immune status of the newly weaned pig”
Authors: A.M. Walsh, T. Sweeney, C. J. O'Shea, D.N. Doyle, J.V. O'Doherty
Volume 111, Issue 05, Pages 798-807, doi: 10.1017/S0007114513003280
“Effect of the interaction of seaweed extracts containing laminarin and fucoidan with zinc oxide on the growth performance, digestibility and faecal characteristics of growing piglets”
Authors: C.J. O'Shea, P. McAlpine, T. Sweeney, P.F. Varley, J.V. O'Doherty