FEATURE
SPRAY-DRIED PLASMA PROTEINS Use of spray-dried plasma proteins in aquaculture diets to improve performance and health of farmed fish by J. Polo, J. Crenshaw and J.M. Campbell APC Inc. 2425 SE Oak Tree Court, Ankey, IA 50021, USA
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pray-dried animal plasma (SDP) proteins are a diverse mixture of functional components consisting of immunoglobulins, albumin, fibrinogen, lipids, growth factors, biologically active peptides (defensins, transferrin), enzymes and other factors that have biological activity independent of their nutritional value. Plasma proteins are used extensively in animal feed to increase consumption, growth and nutritional efficiency especially during period of stress such as after weaning in piglets. The beneficial effects of SDP are more noticeable, under production conditions, when animals are exposed to greater stressors such as pathogens and other environmental variables typically existing under intensive farming conditions, than under conditions of low incidence of pathogens. Numerous challenge studies with pathogenic bacteria, viruses or protozoa have shown a reduction in mortality and morbidity when feeding animal plasma (bovine or porcine origin) to different animal species (pigs, calves, poultry, trout and shrimp). Studies of the mode of action of SDP suggest that the consumption of plasma proteins improves immune system efficiency; therefore, more energy and nutrients from the diet can be used for other productive functions, such as growth, by the animal.
using second-use water as environmental stress (Campbell et al 2014), the results showed that the inclusion of SDP improved survival, protein digestibility and biomass, regardless of whether the plasma was incorporated before (3% or 6% SDP In feed before extrusion) or added after (3% or 6% SDP Out) extrusion, demonstrating that the SDP can be applied before extrusion maintaining the improvement in performance (Figure 1). In another study, the inclusion of SDP as a functional protein
Figure 1: Digestibility and survival effect of SDP1 in trout diets under environmental stress
1SDP was incorporated before (3% or 6% In) or after (3% or 6% Out) extrusion. DM = Dry matter; CP = Crude protein
Use of SDP to improve performance in aquaculture
A series of studies have been conducted in laboratories and commercial production lakes to assess the effect of SDP use in aquaculture nutrition. In most studies, a greater weight (biomass) was observed at harvest, higher survival rate, higher homogeneity, and greater resistance to pathogen challenges. In a study designed to evaluate the effects of SDP on feed digestibility and yield of rainbow trout (Oncorhynchus mykiss)
Figure 2: SDP increases the non-specific serum immune response in sea bream, providing protection against potential pathogen infections.
14 | February 2018 - International Aquafeed