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

This paper reports the first use of thin flakes (310-315 mu m 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.