Study on Reduction of Fish Meal Dosage - Case 1. Study in feed of American Largemouth Bass

2 days ago
4 min read

Effect of fish meal to aquaculture farming when its not stable supply and high price:

Feed cost increase

The sharp increase of fish meal price lead to increase of feed cost and feed price.

For example, feed for fish fry or special species increased by 300-1000 yuan per ton; feed for normal aquaculture increased by 120-200 yuan per ton.

Feed quality fluctuation

Due to the tense supply of fish meal, the in-qualification rate increased, resulting in the quality stability of feed and bring bad effect to liver, intestine, somatic color and capacity of anti-stress of aquatics.

Ratio of 17 amino acids in protein less than 85% reaches 46%. Histamine in-qualification rate reaches 58%, while MDA in-qualification rate reaches 30%.

Supply issue

Inventory of fish meal is not enough or only buy for recent use, while the peaking stage of aquaculture feed demand will come shortly, the demand for fish meal, meat meal increases.

Facing the tense supply and high price of fish meal, quality fluctuation, to reduce the use of fish meal become the focus of fish feed producers.

Mytech products SP900 series are designed for aquaculture feed. Through systematic research from 8 Universities or Institutes, 17 projects between Mytech and aquaculture feedmills, 25 trial cases of reducing fish meal, Mytech developed mature and stable programs of reducing fish meal dosage while maintaining feed quality and good production performance. (Breakthrough | Summary of 25 Fishmeal Replacement Solutions for Aquafeed)

Here in this post, we’re going to share with you 3 studies under different formula basis of American Largemouth Bass:

Formula of high dosage of fish meal
Formula of ever-tried lowest fish meal dosage
Reducing fish meal in low protein diet

Fishmeal Reduction Strategies for Largemouth Bass Feed Amid High Fishmeal Prices

Papers published from project of Mytech and Universities.

2023, Tong Li, Jun Jiang. Aquatic Toxicology (IF 4.5, TOP in section 2)

https://doi.org/10.1016/j.aquatox.2023.106616

2025, Ju Zhao, Jun Jiang. Journal of Agriculture and Food Research (IF 6.2, TOP in section 2)

https://doi.org/10.1016/j.jafr.2025.102152

1．Background and trial program

Fish meal dosage in feed of American Largemouth Bass is about 40-50% before when fish meal is under stable supply and normal price. In this trial program, dosage of Peruvian steam fish meal is 46%. We employed different dosage of EHCP (Enzymatic Hydrolysate of Cottonseed Protein) in the formula and reduce fish meal by equivalent of protein level to study on the effect to growth, health and feed cost and select out the premium performance and most economic cost ones.

Grouping	Formula			Evaluation parameters
Grouping	Nutrition level and grouping	Fish meal	EHCP	Evaluation parameters
Control group (M1)	CP 49% EE 9% 4 duplicates each group 50 fishes each duplicate 22g each fish	46.0%	0	Production performance Health of intestine: digestion and absorption, intestinal barrier, etc Health of liver: OTC to induce challenge to liver Feed formula cost: decreased by 130-300 yuan per ton, based on price of fish meal at 15000-17000 yuan per ton
2% EHCP group (M2)		44.3%	2%
4% EHCP group (M3)		42.6%	4%
6% EHCP group (M4)		41.0%	6%
8% EHCP group (M5)		39.2%	8%

2．Result

(1) Growth performance

Based on the high dosage of fish meal, using 2-6% EHCP to reduce fish meal increased growth performance and 4% EHCP achieve the best performance, 6% EHCP group achieve the lowest feed formula cost.

	Control group	2% EHCP group	4% EHCP group	6% EHCP group	8% EHCP group	4% EHCP group improvement
Weight gain rate, %	426.90^ab	472.19^b	512.59^a	449.64^a	423.22^ab	↑ 85.7%
SGR, %/d	1.77^c	1.86^b	1.93^a	1.81^b	1.76^c	↑ 0.16% per day
Feed intake, g/fish	100.37^b	103.46^ab	106.31^a	99.99^b	98.18^b	↑ 5.9 g
FCR	1.05	0.99	0.93	0.99	1.04	↓ 0.12
Feed efficiency	95.04^b	101.4^ab	108.06^a	101.2^ab	96.33^b	——
Survival rate, %	100.00	99.50	100.00	100.00	99.50	——

(2) Growth and health of intestine

Using 4% EHCP and reduce fish meal increases the growth of intestine, improves the tight junction, helps on the repair of intestinal damage, increases anti-oxidative of intestine, further enhance the inflammation resistance.

	Control group	4% EHCP group	Improvement
Intestine somatic index Fold height of intestine Tight junction of intestine			↑ Health condition

T-SOD	10.31^c	23.74^a	↑ 130.3%
CAT	5.80^bc	6.66^a	↑ 14.8%
GST	94.26^b	101.78^a	↑ 8.0%
MDA	33.66^a	24.61^d	↓ 26.9%
Gene express of inflammation factors Pro-inflammation factors IL-1β、TNF-α Anti-inflammation factors IL-10、TGF-β2

(3) Metabolism and health of liver

Under normal conditions

Using 4% EHCP reducing fish meal could improve lipid catabolism, reduce lipid deposition, utilize more fat for energy supply through decomposition, save protein, repair liver oxidative damage and enhance liver antioxidant capacity.

	Control group	4% EHCP group	Improvement
Liver tissue structure Relative area of lipid vacuoles in hepatocytes			The area of lipid vacuoles in hepatocytes decreased.
T-SOD	190.41^c	260.48^a	↑36.8%
CAT	28.47^c	31.55^a	↑10.8%
GST	176.72^b	200.55^a	↑13.5%
MDA	15.67^a	8.32^d	↓46.9%
Adipose anabolic genes
Lipid catabolism gene

Induce OTC challenge

After 13 weeks of normal condition raising, groups are challenged by over dosage OTC to induce oxidative damage of liver. EHCP repairs OTC-induced liver oxidative damage by promoting the MAPK/ NrF2-mediated enzyme antioxidant system and inhibiting the PINK1/ Parkin-mediated mitochondrial autophagy pathway.

	Control group +PBS	Control group +OTC	4% EHCP group +OTC	Improvement
Liver tissue structure Relative area of lipid vacuoles in hepatocytes				Repair liver enlargement and discoloration induced by OTC. Hepatocyte　lysis, necrosis,　nuclear consolidation, and mitochondrial ridge rupture occurred
ROS	b	a	b	↓
MDA	2.55^b	5.43^a	1.52^c	↓ 72%
SOD	112.97^a	97.48^b	110.30^a	↑ 13%
CAT	24.52^a	20.40^b	25.38^a	↑ 24%
GST	100.95^a	79.63^b	98.91^a	↑ 24%
Repair the pathway of OTC damage to liver

Based on study of above, under high dosage of fish meal in the feed of American Largemouth Bass－－－－－－－－－－－

Program of best performance: 4% EHCP achieves the best growth and health performance, obtains the strongest resistance to stresses.
Program of lowest formula cost: 6% EHCP achieves the lowest formula cost, reducing by 130-300 yuan per ton.

Study on Reduction of Fish Meal Dosage - Case 1. Study in feed of American Largemouth Bass

Recent Posts

Comments