Microwave irradiation and pelleting method affected feed chemical composition and growth performance and feed utilization of sex-reversed Nile tilapia, Oreochromis niloticus (L.)

Abstract

Microwave processing and pelleting methods were assessed to improve aquafeed quality for sexreversed Nile tilapia. The 2 9 3 experimental feeds were prepared with and without microwave irradiation of ingredients prior to pelleting with either a meat mincer, extruder or steam conditioner followed by a meat mincer. Five feedstuff ingredients, including fish meal, meat and bone meal, soybean meal, broken rice and rice bran, were irradiated separately at optimal times, according to the thirdorder polynomial regression analysis between in vitro digestibility and microwave irradiation times (r = 0.681-0.942, P < 0.001, n = 42). The prepared feeds were studied for chemical compositions and responses in fish growth performance and feed utilization efficiency. The fish (1.57 AE 0.01 g initial weight) were fed ad libitum for 4 months. All proximate chemical compositions of experimental feeds, except protein, were influenced by microwave processing, pelleting methods or their interaction (P < 0.05). There were no significant effects from either parameter on water quality during the fish trial. Fish fed steamed microwave-irradiated feed, mechanically pelleted with a meat mincer, showed the highest growth performance (weight gain 18.91 AE 0.73 g and specific growth rate 2.15 AE 0.26% day À1 ) and feed utilization efficiency (feed conversion ratio 1.31 AE 0.05 g feed g gain À1 and protein efficiency ratio 2.27 AE 0.08 g gain g protein À1 ) compared with the other dietary groups. These findings indicate that microwave irradiation of feed ingredients prior to steam conditioning followed by mincing can improve aquafeed production quality.

Water depth and feed pellet type effects on growth and feed utilization in the rearing of green turtle (Chelonia mydasLinnaeus, 1758)

“…Similar observations have been reported for yellowtail kingfish, Seriola lalandi (Miegel et al, 2010) and for turbot, Scophthalmus maximus (Xian et al, 2013): decreased feed intake can significantly decrease the protease activity. In addition, the production of floating pellets may not be only improving the degree of starch gelatinization; it can directly denature dietary proteins (Sansuwan et al, 2017). Decreased trypsin activity in the preferred treatment could allow the turtles to use more energy in anabolic processes, such as growth, rather than in catabolism.…”

Single nucleotide polymorphism markers with applications in aquaculture and assessment of its impact on natural populations

“…Females and males can differ in growth rate, which has implications for aquaculture. Sex manipulation is commonly practiced in aquaculture for example in Nile tilapia, Oreochromis niloticus (Mair et al, 1991;Garcia et al, 2016;Sansuwan et al, 2017), (Calhoun and Shelton, 1983), gilthead sea bream, S. aurata (Loukovitis et al, 2012), European sea bass, Dicentrarchus labrax (Martinez et al, 2014) and turbot, S. maximus (Robledo et al, 2015). Early sexual maturation (grilsing) retards growth, increases production times and affects flesh quality in aquaculture.…”

Impacts of Killing Process on the Nutrient Content, Product Stability and In Vitro Digestibility of Black Soldier Fly (Hermetia illucens) Larvae Meals

“…One milliliter aliquots of supernatants were kept at −20 • C for analysis of free amino acids (in vitro protein digestibility, IVPD) and maltose (in vitro carbohydrate digestibility, IVCD), performed according to the trininobenzene sulfonic acid (TNBS) and dinitrosalicylic acid (DNS) methods, respectively. The IVPD and IVCD studies in the supernatant were described in Sansuwan et al [20]. Residues were then filtered through a filter glass crucible in a Fibertec System cold extraction unit.…”