Penaeus vannamei has a shorter intestine, belongs to the goods that are pulled while eating, and can be eaten day and night.
In shrimp farms, shrimp farmers need to feed according to the size of the pond and the density of the culture, but this work is usually done by hand or by bait machine, and the shrimp fry period is fed two to six times a day. In intensive ponds, there are 30 shrimp per square meter and feed needs to be fed 2 to 4 times a day, and we can also increase the frequency of feeding in intensive ponds, but more frequent feeding of feed may require a lot of work, because the use of bait feed is not common in shrimp farming.
Is it really good to complete the feeding of the pond in a short period of time and in a few times?
Feeding the pond in a relatively short period of time seems to be a good shrimp farming strategy. Some previous studies have concluded that it is not beneficial to increase the number of shrimp feedings two or three times a day, but recent findings contradict these conclusions.
Arnold and his colleagues (2016) reported that feeding black tiger shrimp (P. vanilla) 6 times can significantly reduce the feed conversion coefficient (FCR) and accelerate growth compared to feeding it twice a day.
Jescovitch et al. (2018) report that feeding white shrimp (vannamei) with an automatic bait feeder has led to a significantly faster growth rate of shrimp and a significant increase in weight and yield compared to two manual feedings per day.
Because shrimp eat slowly, long-term feed exposure to water may lead to the loss of important nutrients, including amino acids (AAs). As the content of fishmeal in seafood declines, amino acid additives become more common in shrimp feed, requiring shrimp farmers to adopt more advanced feeding strategies.
A study on feeding feed
What was used in the study was a circular blue tank with a bottom diameter of 1.14 meters, a height of 0.74 meters, and a total area of 1.02 square meters at the bottom. White shrimp was brought to the laboratory from a commercial breeding farm and reared in a coarse pond for 42 days. Then, first determined that the shrimp weigh 1.06 ±0.16 g, a total of 1632 shrimp, which will be placed in 16 tanks of 1 cubic meter, with about 100 shrimp per square meter. Shrimp are first fed on commercially ground feed for 10 days and then fed with different feeds for 70 days.
The feed used in the experiment contained 32% crude protein, and in order to maximize shrimp growth, DL-methionine, L-lysine, L-threonine and L-arginine were supplemented by 0.36%, 1.29%, 0.40% and 0.25%, respectively.
Shrimp are fed in two ways (manual and automatic), two to four times a day by hand, and several times a day by automatic feeder.
Research results and discussions
The findings suggest that white shrimp feeding two to four times a day helps improve shrimp survival, growth rate, and FCR. Our findings are the same as those obtained by other researchers, with increased feeding frequency avoiding feed staying in the water longer, leading to better growth and more efficient feed utilization of Penaeus vannamei.
After 11 weeks of farming practice, it was shown that the frequency of feeding and the time of feeding significantly affected the survival rate, growth rate and feed utilization efficiency of shrimp. Whether it is day or night, when the shrimp are fed multiple times, the survival rate of the shrimp will be higher. However, there was no difference in survival when using hand feeding two to four times a day.
Shrimp growth rate also increases with the increase in feeding frequency, with 0.67 ±0.06 grams of weight gained per week after feeding twice a day, but four or more feedings per day increased the weight of shrimp by 0.91±0.03 grams per week. At the same time, manual feeding of feed compared with machine feeding feed, manual feeding four times a day, weight (10.95± 1.33 g). However, when feeding shrimp using a machine, the weight is (11.33±0.67 g). Therefore, it is stated that by increasing feeding several times a day, the use of machine feeding can significantly increase the yield,
There is also a positive effect on the FCR (feed conversion rate) when fed more times a day. After multiple feedings, the FCR dropped significantly from 2.46±0.31 (twice a day) to 1.59±0.08. When comparing multiple feedings during the day with multiple feedings during the day, it was found that there was no improvement in the FCR when feeding multiple times during the day.
The foods used in this study contained only 3% fishmeal and crystalline amino acids (CAAs), including DL-methionine, L-lysine, L-threonine, and L-arginine, to avoid nutrient deficiencies. Xie et al. (2017) studies show that the addition of DL-methionine makes nutrients more easily degraded.
In another study, Niu et al. (2018) noted that the feed would gradually lose stability from 2 h after being put into the water and decrease significantly after 4 h. This indicates that the decline in food nutrients is proportional to the time it takes to enter the water body. Although we did not measure the decline in amino acids (CAAs) in water, feeding less a day leads to prolonged feed contact with water, which causes nutrients to be rapidly water-decomposed before shrimp eat.
The study by Velasco et al. (1999) expressed the same view, and we observed that shrimp were fed multiple times during the day and at night, compared to multiple times during the day, and the survival rate, FCR and yield of shrimp improved.
Recommendations on how to feed the shrimp
To reduce the use of fishmeal, the addition of nutrients, especially amino acids (AAs), is becoming a common practice for shrimp feed producers. Our findings suggest that feeding multiple times a day helps to improve the viability, growth rate and feed use efficiency of Vannabin shrimp.
Although there have been significant advances in shrimp nutrition research, reducing the use of important nutrients still poses some challenges. Because there is no viable alternative today, increasing the frequency of feeding is the best way to solve this problem.
While it may not be practical to increase the frequency of artificial feeding in shrimp farms, shrimp farmers use automatic feeders to complete the feeding process.
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