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Chemoreception studies in relation to feeding responses in the marine shrimps Penaeus indicus H. Milne Edwards and Metapenaeus dobsoni Miers.

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Title Chemoreception studies in relation to feeding responses in the marine shrimps Penaeus indicus H. Milne Edwards and
Metapenaeus dobsoni Miers.
 
Creator Fernandez, Cheryl Hyacinth
 
Subject Theses
Food and Feeding
Prawn and Prawn fisheries
 
Description Chemoreception in relation to feeding and the various factors involved in
the same in Penaeus indicus and Metapenaeus dobsoni were investigated under
laboratory and field conditions by behavioural and ongrowing studies . The
entire sequence of feeding behaviour in shrimps from appetitive behavioural
pattern to the consumatory act of feeding can be released by chemical stimuli
alone. The chemotactic indices, Db and Rb, developed were used to classify
the feeding stimuli as attractant and repellent based on their chemotactic
property.
Analysis of extracts of natural food materials for both species showed
that they are attractive to !.indicus and ~ . dobsoni, whereas the squid ink
acted as a feeding repellent for shrimps. The feeding response increased with
increase in extract concentration and decreased with squid ink concentrations.
The major attractant and stimulant substances present in the extracts were
free amino acids with 78.2% of the extract activity in !.indicus and 50 . 28% in
~ . dobsoni, and nucleotides. Soluble proteins and peptides, lipids and
carbohydrates also evoke feeding response but at lower level .
Among the various groups of aminoacid; neutral followed by basic amino
acids and among nucleotides; Inosine Mono Phosphate (IMP) produced maximum
feeding response. At the same concentration L-Amino acids were found more
stimulatory than the corresponding DL-amino acid. The threshold concentration
of L-amino acids ranged between 4 x 10-2M and 1 x 10-10M for P. indicus and 1.5
to 1
-10
x 10 M for ~. dobsoni, and in the case of DL-forms it is between 1 x
10-2M and 1 x 10-5 M for both species. Amino acids like lysine, methionine,
glycine, alanine and proline in P. indicus and lysine, methionine, alanine,
ii
phenylalanine and leucine in M. dobsoni produced maximum feeding response and
feed ingestion. Most of the amino acids have anyone of the feeding activity,
but those like glycine and lysine acted differently as attractants, incitant
and stimulant at progressively increasing concentrations.
Environmental parameters like pH and salinity have pronounced influence
on the chemoreception and feeding response in the shrimps, being
chemotactically more active at pH between 7.0 and 9.0 and salinity between 15
and 25%. • The feed intake reduced by 50% at pH 6.0 and 10.0. The alertness
towards feeding stimuli increased with the degree of starvation upto certain
levels and thereafter decreased due to the physical weakness of the animal.
The agar matrix bioassay served as a cheap and efficient method to screen
a wide variety of attractants and stimulants .
Flavouring the diets with potential natural and synthetic chemo
attractants and stimulants reduced the time required' to attract the shrimps to
the feed and to initiate ingestion activity . It also improved the
palatability and acceptability and subsequently improved food intake, growth,
survival, food assimilation efficiency, specific growth rate and food
conversion. This marked increase in the food intake and growth could be due
to the increased digestive activity of the pancreatic secretion and the
resultant increase in appetite,
The attractants and stimulants produced more or less the same pattern for
ingestion activity as that elicited during behavioural trial. It also
indicated that the ongrowing performance of various feeding stimuli could be
predicted directly from the behavioural trial.
iii
The chemoreceptors most concerned with feeding seemed to be on the
antennules, on the pereopods and on the mouth parts. Antennu1e
chemoreceptors were involved in distance chemoreception and to mediate arousal
and search for potential food . The mouth and leg receptors functioned mainly
as contact chemoreceptors; involved in the seizure and ingestion activity and
to some extent they are also involved in distance chemoreception.
Morphologically distinct chemosensory sensi11a present on these appendages
were the primary sites for chemoreception in these species .
Both P.indicus and M.dobsoni differed significantly in their chemotactic
response to different stimuli. Among the various stages of animals studied
juveniles were chemotactically more active than the post-larvae and juveniles.
 
Date 1995
 
Type Thesis
NonPeerReviewed
 
Format application/pdf
 
Language en
 
Identifier http://eprints.cmfri.org.in/7022/1/TH-70_Che.pdf
Fernandez, Cheryl Hyacinth (1995) Chemoreception studies in relation to feeding responses in the marine shrimps Penaeus indicus H. Milne Edwards and Metapenaeus dobsoni Miers. ["eprint_fieldopt_thesis_type_phd" not defined] thesis, Cochin University of Science and Technology.