Effects of algal supplementation in feed to broiler breeders on transfer of nutrients and antibodies to chicks and quality of hatchlings

Breeder nutrition is an important factor for chick quality since the chick embryo relies on nutrients available in the egg for growth and development. In addition, the egg is providing the chick with important antibodies that are vital during the first weeks of life. Brown algae contains several bioactive compounds, and dietary supplementation with algal extracts have shown improved gut health and immune responses in both pigs and poultry. The aim of this study was to investigate if feeding the brown algae Saccharina latissima, intact or as an extract, to broiler breeders can affect breeder hens' antibody responses to vaccination, egg quality and transfer of antibodies and nutrients to the egg and thereby improve the quality of newly hatched chicks. Forty-five hens and nine roosters of the parent lines of the fast-growing broiler Ross 308 were included in the experiment where hens were 31 weeks at the start. The hens were housed individually and fed one of three dietary treatments for seven weeks; (a) control, (b) addition of 0.6% algal meal or (c) addition of 0.08% algal extract. The hens were given a booster vaccination against infectious bronchitis virus (IBV) 21 days after the start of experiment. During experimental days 32-42, hens were naturally mated every 5th day and hatching eggs were collected. A total of 255 chicks were hatched, and chick quality was assessed. Moreover, on chick day three, blood was collected from 48 focal chickens and total immunoglobulin Y levels and specific titres to IBV in serum were determined. The results showed that feeding the brown algae Saccharina latissima, intact or as an extract to broiler breeders did not affect egg production, egg quality, antibody responses to vaccination or transfer of antibodies from hen to chick. However, feeding intact algae significantly increased the levels of iodine and decreased the level of selenium in the eggs and resulted in a lower proportion of chicks with maximum quality score. Interestingly, algal feeding, both intact and as an extract, increased the abdominal fat pad in broiler breeders by about 17% without affecting BW. In conclusion, supplementation of broiler breeder diets with algal extract from Saccharina latissima, but not intact algal meal is a promising dietary strategy to increase the abdominal fat pad without causing any adverse effects on nutrient level in eggs or chick quality.

Removal of dissolved brown algal phlorotannins using insoluble polyvinylpolypyrrolidone (PVPP)

Tannins, a large and diverse group of phenolic secondary metabolites, are common in terrestrial plants and marine brown algae. It is sometimes desirable to remove the tannins from plant or algal extracts, e.g., when isolating enzymes and nucleic acids, when using certain colorimetric methods to quantify the tannin content, or to create reliable controls when using tannins in experimental studies. Insoluble polyvinylpolypyrrolidone (PVPP) can be used to specifically remove tannins from solution. In the present study, we evaluated the effect of different factors (amount of PVPP, number of PVPP treatments, type of solvent, pH, and incubation time) on the PVPP removal of dissolved brown algal phlorotannins. Our results imply that there is a limited amount of phlorotannins that can bind to a given amount of PVPP, and that it is preferable to use low quantities of PVPP repeatedly, compared to using fewer treatments with a high amount of PVPP. Furthermore, we found no consistent effect on the removal of phlorotannins due to solvent type (acetone, methanol, distilled water or filtered seawater). There was a slight decrease in the amount of phlorotannins removed from extracts with increasing pH when repeatedly treated with PVPP. All phlorotannins were removed from extracts with pH < or = 6.2, and 89% of the initial phlorotannin content was removed at pH 9.7. These results are compared with previous methodological studies on tannin removal with PVPP. Furthermore, the implications of phlorotannin removal in analytical and ecological investigations are discussed.

Water-borne cues induce chemical defense in a marine alga (Ascophyllum nodosum)

It is well known that herbivores can induce chemical defenses in terrestrial vascular plants, but few examples of inducible production of defense chemicals have been reported for aquatic macrophytes. Furthermore, it is well established that water-borne chemical cues from predators or predator-wounded conspecifics can induce defensive changes of aquatic prey animals, but no such communication between aquatic herbivores and seaweeds has been reported. Here we show that water-borne cues from actively feeding herbivorous gastropods, flat periwinkles (Littorina obtusata), can serve as external signals to induce production of defense chemicals (phlorotannins) in unharmed individuals of seaweeds, knotted wrack (Ascophyllum nodosum), and that the increased levels of defense chemicals deter further feeding by periwinkles. Because seaweeds have poorly developed internal-transport systems and may not be able to elicit systemic-induced chemical defenses through conveyance of internal signals, this mechanism ensures that seaweeds can anticipate future periwinkle attacks without receiving direct damage by herbivores.