Alternative methods for nutrition research on the southern bluefin tuna,Thunnus maccoyii(Castelnau): evaluation of Atlantic salmon,Salmo salarL., to screen experimental feeds

Abstract

Development of a formulated pellet to replace ‘bait’ fish in farmed southern bluefin tuna (SBT), Thunnus maccoyii (Castelnau), feeds is in progress; however, inherent difficulties have been encountered in conducting large‐scale growth trials to evaluate experimental pellet quality. Consequently, alternative methods are being investigated to develop a suitable feed more rapidly. This work explored whether Atlantic salmon, Salmo salar L., could be used as a ‘surrogate’ species for nutrition research on SBT by screening experimental SBT feeds. Atlantic salmon (initial mean weight 161.4 g) were fed a commercial salmon feed (Com.Sal), a commercial northern bluefin tuna feed (Com.NBT), one of three experimental SBT feeds (CRC‐A, ‐B, ‐C) or dry pelleted pilchards for 42 days, at which time growth was assessed. In vivo and in vitro protein digestibility of the feeds was also evaluated. Weight gain of Atlantic salmon fed Com.Sal (99.8 g) and Com.NBT (93.5 g) were found to be significantly (P < 0.01) greater compared to those fed CRC‐C (68.2 g) and pilchard (56.1 g). Weight gain of salmon fed the CRC‐A (81.6 g) and CRC‐B (85.3 g) were also significantly different from the pilchard‐fed group, but not from CRC‐C. No significant correlation was found between salmon and SBT growth, although difficulties with conducting growth trials on SBT may have limited the ability to compare data. In vitro ingredient digestibilities, however, were used to predict whole feed digestibility, which was found to significantly correlate to weight gain in SBT. Although the use of digestibility techniques appears useful in formulating SBT feeds, the use of a ‘surrogate’ species such as Atlantic salmon to screen SBT feeds needs to be more fully investigated.

Effect of phytic acid and phytase on feed intake, growth, digestibility and trypsin activity in Atlantic salmon (Salmo salar, L.)

“…Atlantic salmon were obtained from Springfield Fish Farm (Scottsdale, Tasmania, Australia) and transferred to the School of Aquaculture, University of Tasmania. Fish were kept in 300-L circular tanks in a recirculation system where water quality was maintained through physical and biological filters (Bransden et al 2001). Fish were maintained on a commercial feed (2 mm Salmon, Skretting Australia, Cambridge, Tasmania, Australia) for 2 weeks.…”

Upcycling biomass in a circular food system : The role of livestock and fish

“…The nutrient content of these phase specific feeds is provided in Table S3.5. (60-200g) 12.00 32.00 Grower (200+ g) 11.60 30.00 Broodstock 12.00 32.00 Anderson et al (1992) 12 Opstvedt et al (2003) 13 Zhang (2011) 14 FAO (2018a) 15 Hajen et al (1993) 16 Bransden et al (2001), Carter et al (1999) 17 Cho (1990) 18 Gaylord et al (2008) B4 -Nutrient content of animal sourced food…”