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Aquaculture 186 Ž2000 89–105
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www.elsevier.nlrlocateraqua-online

Protein digestion in penaeid shrimp: digestive

proteinases, proteinase inhibitors and feed
digestibility

b
D. Lemos a,) , J.M. Ezquerra , F.L. Garcia-Carreno ˜ c
a
´
˜
˜
Instituto Oceanografico, UniÕersity of Sao Paulo, P.O. Box 66149, 05389-900 Sao Paulo, SP, Brazil
b
UniÕersity of Sonora, DIPA, P.O. Box 1658, Hermosillo, Sonora 83000, Mexico
c
´
)
Centro de InÕestigaciones Biologicas del Noroeste (CIBNOR , P.O. Box 128, La Paz, BCS 23000, Mexico
Accepted 11 November 1999
Abstract
Protein is the most abundant ingredient in both natural and prepared diets of penaeid shrimp.
The assessment of protein digestion through the developmental stages of penaeids may contribute
to the development of more suitable feeding schedules for their cultivation. Among the techniques
to study protein digestion, detection and characterization of digestive proteinase inhibitors in
proteinaceous feed ingredients can be achieved by substrate- wsodium dodecyl sulphate polyacryl-
amide gel electrophoresis x ŽSDS-PAGE . In vitro assays of protein digestibility are also useful
.
tools when testing alternative protein sources in the formulation of shrimp feeds. The present
article reviews three methods that have been used to assess protein digestion: Ž. 1 detection and
characterization of proteinase activity and proteinaceous proteinase inhibitors by substrate-SDS-
PAGE, Ž. 2 quantification of proteinase activity, and 3 in vitro evaluation of digestibility of
Ž.
dietary protein sources by shrimp proteinases. A compilation of previously reported and unpub-
lished data on some aspects of penaeid protein digestion is presented. Trypsin activity of
Litopenaeus schmitti varied considerably during larval and postlarval development, showing the
highest value at protozoea III. The molecular weight of digestive proteinases from early stages of
Farfantepenaeus paulensis also differed from the adult pattern, and some activity bands could be
characterized as trypsin in adult F. paulensis. The digestive proteinase pattern of adult Farfante-
penaeus californiensis, F. paulensis, L. schmitti and Litopenaeus Õannamei in SDS-PAGE
showed clear differences among these species, which may be evidence of a species-specific
pattern of protein digestion. In vitro evaluation of digestibility of aquafeeds can be achieved by the
pH-stat method, which can help in the choice for alternative protein sources. Moreover, the quality

)
Corresponding author. Fax: q55-11-210-3092.
E-mail address: dellemos@usp.br ŽD. Lemos .
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0044-8486r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved.
PII: S0044-848 Ž 6 99 00371-3
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