Palatability of Protein Hydrolysates from Industrial Byproducts for Nile Tilapia Juveniles

Abstract

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.

Attractability and palatability of liquid protein hydrolysates for Nile tilapia juveniles

“…This equation was elaborated with the data of the present study, presenting satisfactory results with the data described by Alves, Oliveira, et al () no article “Palatability of protein hydrolysates from industrial by‐products for Nile tilapia juveniles” (Table ).…”

“…Amino acids represent chemical signals in the gustatory system of fish, which are classified as inciting or stimulant and may differentiate the attractiveness of a feed. Among them, there can be highlighted: cysteine, betaine, glutamic acid, serine, glycine, alanine, proline, methionine, cysteine, phenylalanine, arginine, tyrosine, valine, leucine and glutamine (Kasumyan & Morsi, ; Kasumyan, ; Kasumyan & Doving, ; Hara, ; Suresh, Vasagam, & Nates, ; Kasumyan & Sidorov, ; Lokkeborg et al, ; Siikavuopio, James, Stenberg, Evensen, & Saether, ; Alves, Silva, et al, ; Alves, Oliveira, et al, ).…”

“…After data collection, the footages were examined in order to analyse the following feeding behaviours (Alves, Silva, et al, ; Alves, Oliveira, et al, ): (a) time to capture the first pellet (seconds); (b) number of pellet rejection after capture; (c) number of approaches without capturing the pellet; and (d) number of consumed pellets. The attractability and palatability index was then calculated for each treatment.…”

“…The index formula of attractability and palatability (IAP) was desenvolved using feeding behaviours all: time to capture the first pellet (seconds); number of pellet rejection after capture; number of approaches without capturing the pellet; and number of consumed pellets. All of these eating behaviours were used to develop IAP because they presented satisfactory data to assess attractiveness and palatability as described by Alves, Silva, et al (), Alves, Oliveira, et al (). The analyses were performed with the aid of the software MATLAB.…”

“…Thus, the aim of this study was to determine the attractability and palatability of liquid protein hydrolysates made of swine mucus (PHM) formed by by‐products of heparin production and liquid protein hydrolysates made of poultry (PHF) formed by viscera, muscles, liver, gizzard and other poultry for Nile tilapia juveniles. We tested experimental diets (based on dry matter) with different protein content and hydrolysates and with different free amino acid content than our previous study (Alves, Silva, et al, ; Alves, Oliveira, et al, ). Use of these newly prepared diets gave higher attractability and palatability indices.…”