29
Control diet
SDP diet
Energy (MJ/kg)
24.1 ± 0.1
24.1 ± 0.0
Energy (kcal/100g)
483.6 ± 2.0
483.1 ± 0.9
Moisture (%)
7.8 ± 0.1
7.9 ± 0.0
Protein (%)
46.9 ± 0.2
47.5 ± 0.1
Crude Fat (%)
27.2 ± 0.4
27.2 ± 0.2
Ash (%)
4.8 ±0.0
4.9 ± 0.0
*NFE (%)
12.8 ± 0.3
12.1 ± 0.3
Crude fiber (%)
0.4 ± 0.0
0.4 ± 0.0
*NFE, nitrogen free extract Table 1. Nutritional composition of study feeds (means ± SEM).
Figure 1. Tank average weight at the end of the study and weight increase during the whole period (90 fish per tank, three tanks per group). Dots represent tank average; lines represent mean and s.e.m.
SDP in aquaculture The nutrition provided by the inclusion of SDP in the diet of farmed fish improves both growth performance, digestibility, feed efficiency and size homogeneity in different fish species like trout, sea bream, Nile tilapia and in shrimp (Polo et al., 2018; De Muylder et al., 2019). In gilthead sea bream, studies indicated that the inclusion of SDP enhanced the intestinal and serum innate immune function, the activity of the intestinal antioxidative stress
enzymes and promoted somatic growth (Gisbert et al., 2015). Furthermore, due to the health effects associated with the use of SDP, it has been extensively used as a key tool to reduce the use of ATB growth promoters in different farm animals, including pigs, calves and poultry (Torrallardona, 2010; Campbell et al., 2019). This functional protein can be a strategic ingredient that can be used in programs aimed to reduce the use of ATB growth promoters in high quality fish and shrimp production. 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). Knowing that SDP can modulate the immune function in fish, Araújo et al. (2017) demonstrated that feeding SDP to Nile tilapia submitted to cold stress improved immune function and cold resistance.
SDP in challenged salmon A recent study focused on evaluating the supplementation of SDP on growth parameters in post-smolts Atlantic salmon submitted to SRS challenge. The trial was conducted at indoor facilities of the research institute of VESO-Chile (Port Montt, Chile). Five hundred forty post-smolts Atlantic Salmon (91.5 g, BW) were distributed in six tanks maintaining equal biomass and fish density randomized in two treatment groups with three replications per treatment. Dietary treatments were 0% (control) or 3% of SDP (AP920; APC Inc). Diets were formulated to contain similar nutrients and energy (Table 1). On week 10 of the study, the fish were challenged with Piscirickettsia salmonis to cause Salmon Rickettsial Syndrome (SRS; EM-90 like strain) by cohabitation method. Study length for performance parameters was for 11 weeks. To study if SDP could influence survival to SRS, the study continued for additional weeks but no performance parameters were obtained at that time.
Groups BW increase (g) Control 135.4
Biomass increase (g) 9,996
SGR TGC 1.06 5.63
10,625
1.11 5.91
SDP 143.3
Table 2. Growth performance and biomass increase during the trial. Mean specific growth rate (SGR, %BW/d), thermal growth coefficient (TGC), weight increase (based on average weight, g), biomass increase (based on average tank biomass, g).
Aquafeed: Advances in Processing & Formulation Vol 12 Issue 1 2020