Flakes versus noodles as feed for the abalone Haliotis asinina, does form matter?

Abstract

This paper reports the first use of thin flakes (310–315 μm thick) formulated diets as feed for the abalone Haliotis asinina. The study compared noodles and flakes prepared using refined and unrefined diets developed earlier for H. asinina (Bautista-Teruel et al., J. Shellfish Res., 35, 2016, 633). Four treatment diets in triplicates (refined flakes, MBTr-F; refined noodles, MBTr-N; unrefined flakes, MBTur-F; and unrefined noodles, MBTur-N) were used in a feeding experiment conducted in a tank facility. After three months, abalone fed MBTr-F had significantly higher mean shell length and body weight (35.92 ± 0.36 mm, 9.24 ± 0.29 g) compared with those fed MBTr-N (34.63 ± 0.37 mm, 8.22 ± 0.28 g) and MBTur-N (34.23 ± 0.36 mm, 7.66 ± 0.26 g), but did not significantly differ with those fed MBTur-F (35.40 ± 0.30 mm, 8.57 ± 0.24 g). Likewise, abalone fed MBTr-F had significantly higher mean growth rates (5.31 ± 0.08 mm, 2.59 ± 0.06 g/month), compared with those fed MBTr-N (4.90 ± 0.19 mm, 2.26 ± 0.12 g/month) and MBTur-N (4.71 ± 0.02 mm, 2.07 ± 0.06 g/month), but did not significantly differ with those fed MBTur-F (5.11 ± 0.06 mm, 2.37 ± 0.04 g/month). Survival (96.67–98.89%) and FCR (2.2–2.5) did not significantly differ among treatment diets. Between the flaked diets, MBTur-F is the cheaper option. However, the use of this unrefined diet resulted in distinct turquoise abalone shell colour, not observed in those fed MBTr-F.