This study was performed with the aim of determining the palatability of diets containing poultry and swine protein hydrolysates for Nile tilapia. Five experimental diets were made with a 5% inclusion level of fishmeal (FPE), poultry protein hydrolysate (PHF), liquid swine hydrolysate (PHS), feather protein hydrolysate (PHP), and swine mucosa hydrolysate (PHM). Five juveniles (2.81 ± 0.17 g) were placed in 10 L aquariums and fed five times a day after a raffle of offered diets. In each feeding throughout the day, 30 pellets were offered per fish. The experimental design was completely randomized, with five replicates per day. A three-minute footage period was established for each feeding with a digital camera. The following feeding behaviors were observed: time to capture the first pellet, number of pellet rejections, number of approaches without capturing the pellet, and number of consumed pellets. No observed parameters presented significant differences (p > 0.05). PHF provided a palatability index of 12.27%, while PHM had an index of 9.33%, PHF of 8.77%, and PHP of 7.74%. Both diets PHS and PHM increased the final consumption of pellets in comparison to FPE by more than 10%, despite the absence of a significant effect.

The experiment was conducted with the aim of determining the attractability and palatability of liquid protein hydrolysates for Nile tilapia. Five experimental diets were formulated containing 5% inclusion of fishmeal (FPE; positive control), 5% inclusion of liquid protein hydrolysate of porcine mucosa (PHM), 5% inclusion of liquid protein hydrolysate of poultry (PHF), 5% inclusion of liquid fish oil (OPE) and a diet without fishmeal (negative control). Five juveniles (2.51 ± 0.13 g) were distributed in 10 L tanks, and the animals were fed five times a day, with a previous draw being made of the offered diets. The same amount of pellets was offered and the following feeding behaviours were evaluated with the aid of three‐minute footages per feeding: time to capture first pellet, number of rejections, number of approaches without capturing the pellet and number of consumed pellets. None of the observed parameters displayed significant differences (p > .05), and all diets presented negative palatability indexes in comparison to FPE. The SPE diet provided a attractability and palatability index of 6.17%, while OPE index was 2.87%, PHM 2.82% and PHF 2.74%. Both PHF and PHM reduced the final consumption of pellets in comparison to FPE in approximately 28% and 20%, respectively, although it did not present significant values.

B. splendens, a worldwide widespread species (Alderton & Guibbs, 2011), belongs to the anabantid family and has a carnivorous feeding habit, a wide variety of colours, sizes, openings and shapes of the tail fin, in addition to the ability to capture atmospheric oxygen and little demand for management, outstanding characteristics of the species.In all its breeding stages, quality food is of fundamental importance for the proper development of Bettas (Faria et al., 2006). However, adequate feed formulations are essential for the good development of a species (Furuya, 2010; NRC, 2011). In fish diets, the main protein source of animal origin used is fishmeal, however, due to the high demand and environmental consequences of this ingredient, a reduction in its supply is expected (Silva et al., 2017).Thus, the aquaculture food industry seeks to adapt by investigating alternative protein sources with high availability in the market and attractive palatability that can be included in diets for fish, thus reducing food waste (Apper et al., 2016;Tantikitti, 2014).Currently, factors such as availability, good biological quality and low cost of agro-industrial co-products arouse interest in their use in animal

This study determined the compelling palatability of Atractus AQVA® flavoring for Nile tilapia juveniles (Oreochromis niloticus). Five isoproteic (40% crude protein) and isoenergetic (3,420 kcal kg-1) experimental diets were elaborated containing 0.25 (A25), 0.50 (A50) and 0.75% (A75) flavoring inclusion, a positive control diet with 10% fishmeal (FPE) and a negative control without fishmeal (SPE). Five juvenile individuals (2.58 ± 0.27 g) were distributed in five 10 L tanks and were fed four times a day with one of the diets, randomly raffled. The same number of pellets was offered, and the following behaviors were observed: time to capture the first pellet, number of pellet rejections, and number of approximations without capture and consumed pellets in each feeding event, using three-minute recordings with a digital camera. A significant effect (P < 0.05) was found regarding the number of approximations without capturing the pellet, as well as a higher palatability index for A75, followed by A50, A25, SPE and FPE. Therefore, it was concluded that A75 provided the highest compelling palatability of all diets by increasing the palatability index by 10.49% and displaying a 23.13% reduced rejection of pellets, besides presenting a 3.3 fold reduction in the number of approximations without capturing pellets with diet FPE.

This study aimed at determining the compelling palatability of different protein hydrolysates for Nile tilapia juveniles (Oreochromis niloticus). Four isoproteic (30% crude protein) and isoenergetic (3,200 kcal kg -1 ) experimental diets were formulated, with a 5% inclusion level of poultry hydrolysate protein (PHF), or swine liver hydrolysate protein (PHS), or feather hydrolysate protein (PHP) and a control treatment containing 5% of fishmeal (FPE). Four juveniles (2.9 ± 0.01 g) were distributed in 10 L tanks and fed four times a day, and before each feeding event, diets were drawn. The same amount of pellets from each diet was offered, and feeding behaviors were recorded during three minutes for each feeding event, referred to the time of capture of the first pellet, number of pellet rejections, and number of approximations without capturing pellets and quantity of consumed pellets. A significant effect (P < 0.05) was observed regarding a higher consumption of pellets and palatability index for PHF, followed by PHS, FPE, and PHP. Therefore, it was concluded that PHF provided the highest compelling palatability for Nile tilapia juveniles, by displaying a 10.82% increase of the palatability index, 17% of final feed consumption, and presented a rejection number 6.89 times lower than FPE.