# Effects of dietary replacement of fish meal by defatted black soldier fly larvae on growth performance, blood profiles, immune response, and diarrhea incidence in weaning pigs

## TL;DR

This study found that replacing up to half of fish meal with black soldier fly larvae in pig diets does not harm pig growth or health and may even improve some blood markers.

## Contribution

The study demonstrates that defatted black soldier fly larvae can replace up to 50% of fish meal in weaning pig diets without adverse effects.

## Key findings

- Replacing fish meal with black soldier fly larvae up to 50% did not significantly affect growth performance in weaning pigs.
- Increased BSF larvae levels led to trends of improved feed intake and changes in blood metabolites like creatinine and glucose.
- No negative effects on immune response or diarrhea incidence were observed with up to 50% replacement.

## Abstract

The purpose of this experiment was to evaluate the effects of dietary replacement of fish meal (FM) by black soldier fly (BSF) larvae on growth performance, blood profiles, immune response, and diarrhea incidence in weaning pigs.

A total of 160 weaning ([Yorkshire×Landrace]×Duroc) pigs (7.47±0.02 kg body weight [BW]) were assigned to four treatments according to sex and initial BW, with five replicates of eight pigs per pen in a randomized complete block design. Experimental diets with BSF larvae replaced FM at 0%, 25%, 50%, and 100% for phase I (0 to 2 weeks). During the phase II (3 to 4 weeks) treatments were as follows: 1) Control: corn-soybean-based diet containing FM 4%, 2) BSF25: corn-soybean-based diet containing FM 3% and BSF larvae 1%, 3) BSF50: corn-soybean-based diet containing FM 2% and BSF larvae 2%, 4) BSF100: corn-soybean-based diet containing BSF larvae 4%.

There were no significant differences among the treatment groups in BW and average daily gain during the experimental period. However, an increased tendency of average daily feed intake was observed (linear, p = 0.09), and gain to feed ratio tended to decrease as the replacement rate of FM with BSF larvae increased (linear, p = 0.06). During phase I, creatinine concentration decreased linearly as BSF larvae level increased (linear, p = 0.02). During phase II, the glucose concentration linearly changed as an increase in BSF larvae level (linear, p = 0.02). Meanwhile, pigs fed with increasing BSF larvae levels showed increased albumin and total protein concentration trends (linear, p = 0.05, p = 0.05).

In weaning pig diets, defatted BSF larvae can substitute up to 50% of FM without negatively affecting immunological response, blood metabolites, or performance. These encouraging results imply that BSF larvae may be a viable and efficient substitute for FM in pig diets.