Effects of feed rations containing egg powder in different proportions on growth performance, feed utilization, body composition and survival rate of rainbow trout (Oncorhynchus mykiss Walbaum, 1792) fry

Abstract

This study aims to determine the appropriate egg powder ratio that can be substituted into the fish meal to close the protein deficit without adversely affecting the development performance of rainbow trout fry (Oncorhynchus mykiss) (0.38±0.01 g and 3.55±0.05 cm). Also, the effects of egg powder used as a protein source on rainbow trout feed on growth performance, feed utilization, body composition, and survival rates were investigated. The egg powder ratio in the ration of the groups were arranged to be 0% (Control), 25% (E-25), 50% (E-50), 75% (E-75), and 100% (E-100) of the amount of protein obtained from fish meal. To evaluate their growth performance, fish were fed for 90 days between March and May, and additional feeding was given for 17 days for the challenge test. As a result of the study, when the more than 25% egg powder was added to the ration, the final body weight (FBW), weight gain (WG), weight gain rate (WGR), specific growth rate (SGR), feed intake (FI), and protein efficiency ratio (PER) had a statistically significant difference among the groups (p<0.05). It was determined that the difference between groups was insignificant in terms of condition factor (CF), and the addition of more than 25% egg powder to the ration increased the feed conversion ratio (FCR) statistically and significantly (p<0.05). As a result of the challenge test carried out with two different fish pathogens (Lactococcus garvieae and Yersinia ruckeri), it was determined that the addition of egg powder decreased the survival rate in all groups compared to the control group (p <0.05). As a result, it was concluded that up to 25% of egg powder can be used rainbow trout fry feeds, but continuous feeding with egg powder supplemented feeds may cause fish health problems.

Dandelion Root Extract in Trout Feed and its Effects on the Physiological Performance of Oncorhynchus mykiss and Resistance to Lactococcus garvieae Infection

“…The DRE added to the diet increased the crude protein content in the muscle and liver as the concentration of the extract increased from 0 to 20 mL/kg, while the crude lipid content decreased compared to that in the control group. Similar findings were reported in studies on the rainbow trout and Trachinotus ovatus fish with dandelion extract applied to the diet (Tan et al, 2017;Koshinski, 2020;Köse and Ariman Karabulut, 2022;Mostafavi et al, 2022). As mentioned in our previous study, the feed administered to the fish is utilized more effectively in the presence of dandelion, which positively affects protein and lipid accumulation.…”

“…Researchers have recently started investigating the application of dandelion in the field of aquaculture, although many researchers in other disciplines have studied it. Only a few studies have assessed the growth performance and histological, physiological, and immunological parameters in some fish (e.g., Trachinotus ovatus (Tan et al, 2017;Tan and Sun, 2020), hybrid grouper (Sun et al, 2019(Sun et al, , 2022, Cyprinus carpio (Sirakov et al, 2019), and Oncorhynchus mykiss (Koshinski, 2020;Salem et al, 2021;Mostafavi et al, 2022;Köse and Ariman Karabulut, 2022). Additionally, no other bacterial disease resistance has been investigated except for Vibrio harveyi (Tan et al, 2017) and Streptococcus iniae infection (Shekarabi et al, 2021).…”

“…Dandelion was extracted following the method described in our previous study (Köse and Ariman Karabulut, 2022). Briefly, fresh dandelion roots (164.56 g) were dried in a fan-drying oven at 40°C for 3−4 days until constant weight (weight after drying root: 37.84 g), and then, they were ground and sieved through a 500 µm sieve.…”

“…First, the bacteria were incubated in TSB (tryptic soy broth) for 24 h. Then, they were centrifuged at 7392×g and 4°C for 5 min to the supernatant was discarded. The precipitated bacteria were mixed with FTS (physiological saline) to McFarland 0.5 turbidity and prepared for injection (Er et al, 2021;Köse et al, 2021). Based on our previous experience, 0.1 mL (2.8×10 8 CFU/mL) of bacteria were injected intraperitoneally with an insulin syringe (Er et al, 2021;Köse et al, 2021).…”

“…The precipitated bacteria were mixed with FTS (physiological saline) to McFarland 0.5 turbidity and prepared for injection (Er et al, 2021;Köse et al, 2021). Based on our previous experience, 0.1 mL (2.8×10 8 CFU/mL) of bacteria were injected intraperitoneally with an insulin syringe (Er et al, 2021;Köse et al, 2021). During the experiment, the fish were fed thrice a day (9:00 a.m, 1:00 p.m, and 5:00 p.m) at 2% of their body weight with the experimental feed of their respective groups.…”