Effect of probiotics, mineral supplementation and biofertilizers on growth performance of some euryhaline fish species in inland saline groundwater
Loading...
Date
2006
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
CCSHAU
Abstract
In this thesis an attempt has been made to study the role of microbial fertilizers
in pond productivity, role of probiotics, Lactobacillus sporogenes and minerals (Ca-P)
supplementation on growth performance and some aspects of nutritive physiology of
two euryhaline fish species. The thesis is divided into three parts. Part I describes the
role of Azotobacter chroococcum and Gluconacetobacter diazotrophicus 35-47 in
nitrogen fixation and phosphate solubilization in inland saline ground-water ponds
stocked with milkfish, Chanos chanos. Studies have shown significantly (P<0.05)
high values for alkalinity, kjeldahl's nitrogen, NO3-N, turbidity, pigment
concentration and fish growth in ponds inoculated with co-culture (Mac-27+ PS-21),
followed by Mac-27 and PS-21, o-PO4 concentration was significantly (P<0.05) high
both in PS-21 and in mixed culture inoculated ponds. Alkanity, hardness, TDS and
chlorophyll a concentration were significantly (P<0.05) higher in ponds inoculated with high temperature tolerant mutant of A. chroococcum, while total kjeldahl
nitrogen, NH4-N, NO2-N, o-PO4 concentration and fish growth were high in ponds
inoculated with salinity tolerant strain of G. diazotrophicus. Not much variations in
DO concentration were observed among different treatments. Irrespective of
bioinoculants, a significant (P<0.05) increase in viable counts were observed upto day
7 after inoculation, and thereafter a significant decline in microbial population was
observed.
To study the effect of Lactobacillus sporogenes (Probiotics) on growth
performance of Oreochromis niloticus, four diets containing varying concentration
(0.25, 0.5, 0.75 and 1.0g 100 g-1 of diet) of probiotics were formulated. A diet
without supplementation of probiotics was also formulated which served as control
diet. All diets contained about 40% of crude protein. Significantly highest growth
performance, carcass protein, apparent protein digestibility, nutrient retention (PER,
GPR, GER and APD), digestive enzyme activity were observed in the group fed diet
containing probiotics at a concentration of 0.75 g, 100 g-1 of diet. Excretion of
metabolites remained low, while the values of VSI and HSI remained high at this
treatment. Muscle glycogen and liver glycogen were also low, while the values of
muscle protein were high in fish fed diet-3 containing probiotics at a concentration of
0.75g, 100g-1 of diet. These studies indicate that supplementation of diets with
appropriate concentration of probiotics can be a useful tool in the utilization of
supplementery diets in aquaculture.
An experiment was carried out with Chanos chanos and Oreochromis
niloticus to determine their phosphorus requirements and its interaction with dietary
calcium. Ten isoenergetic and isonitrogenous diets were prepared using basal
ingredients (groundnut oilcake, processed soybean, rice bran and wheat flour etc.)
containing various concentration of phosphorus as potassium dihydrogen
orthophosphate (0.25g, 0.375g and 0.5g 100g-1 of diet) and calcium as calcium
chloride (0.5g, 0.75g and 1.0 g 100 g-1 of diet). These concentrations resulted in
varying Ca-P ratios (1:1, 2:1, 3:1, 3:2, 4:1, 4:3, 8:3). Calcium and phosphorus
concentrations in the water at 10 ppt were 425 mg and 0.03 mg l-1 of water,
respectively. Irrespective of the fish species, significantly (P<0.05) high growth
performance (growth per cent gain in body weight, SGR and final length, APD, GPR,
GER and PER were observed in the groups which were fed on a diet containing
calcium and phosphorus at a concentration of 0.5g 100g-1 of diet in the ratio of 1:1.
Low FCR and excretion of metabolites (N-NH4, o-PO4) and significantly (P<0.05)
highest digestive enzyme activity were also observed in fish fed on this concentration.
Low muscle and liver glycogen levels and high muscle protein content coincided with
the highest growth performance observed in these studies. VSI and HSI values were
also high in fish which had the highest growth performance. Carcass composition also
indicated high accumulation of protein. These studies indicated that diets must be
supplemented with minerals especially calcium and phosphorus in optimum
concentrations and ratios for obtaining the full benefit of supplementary diets.