Nutritional analyses were performed on 27 fruit species that are eaten by frugivorous birds in east Mediterranean habitats in Israel. The essential amino acid (EAA) profile [compared by principal component analysis (PCA)] of these fruits indicated two distinct groups of fruits. The main group consisted of 23 species that were similar in their relatively low total EAA quantities and imbalanced EAA profiles. On average, the EAAs phenylalanine and tyrosine were most concentrated and histidine least (tryptophan was not measured). Comparing the relative amounts of EAAs in fruits with required amounts for maintenance of granivorous passerine birds revealed that these fruits are deficient in all or most EAAs. The sulfur-containing amino acids (methionine and cystine) were most limiting relative to the required amount (41-61% below requirement), while four others (arginine, lysine, isoleucine, and leucine) were severely deficient (30-37% below requirement). These results complement reports suggesting that frugivorous birds have lower total protein demands than granivores. The second group of four fruit species had relatively high total EAA contents. Each of these fruits appeared to contain especially large quantities of some EAAs, but it was uncertain whether some high concentrations could have resulted from interactions in the pulp during preparation and chemical analysis.
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Acknowledgments—I thank Y. Pancheshnikova for assisting in the laboratory, and Dr. E. Bamberger and Dr. Z. Shappira for helping during different stages of this study. I am grateful to Franz Bairlein, Mary Murphy, James Sedinger and Doug Levey for comments on a first draft of this manuscript. Amino acid analyses were performed at Aminolab Ltd., under Dr. Z. Harduf's supervision. This study was partly supported by a joint research grant of the Technion andUniversity of Haifa, by the Carmel Foundation-Ministry of Environmental Affairs, and by a grant from the Joint German Israeli Research Program.
- Essential amino acids
- Fleshy fruits
- Plant-animal interactions
- Secondary compounds
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics