Fatty Acids Composition of Stomach Oil of Scopoli’s Shearwater (Calonectris diomedea) from Linosa’s Colony

SIMPLE SUMMARY: Some Procellariiformes use an alternation of short tips and long trips to feed their chick. During these trips, they can accumulate stomach oil in the proventriculus derived from partially digested preys. The stomach oil was collected from adults of Calonectris diomedea from Linosa islands for fatty acids composition investigation. The results showed differences in fatty acid composition between the initial rearing period and the period near fledging. The present work gives a contribution to deepen the ecology and feeding strategies of the C. diomedea colony in Linosa island (Southern Italy). ABSTRACT: Calonectris diomedea is a Procellariforms seabird having a very representative colony in Linosa Island (Southern Italy). The adult forms of C. diomedea produce a pasty oil from their proventriculus to feed their chicks during the rearing period. In this work, we examined the fatty acids composition of the stomach oil of C. diomedea from Linosa Island by gas chromatography with flame ionization detection (GC-FID). The samples were collected at 20 and 70 days after hatching. Twenty different fatty acids (FAs) were identified. Saturated fatty acids (SFA) were the most abundant in percentage (41.6%) at day 20 followed by polyunsaturated fatty acids (PUFA, 38.7%) and monounsaturated fatty acids (MUFA, 19.7%). MUFAs were the most abundant in samples collected at day 70 (53.8%), followed by SFAs (36.6%) and PUFAs (9.8%). Oleic acid (C18:1ω9) in the samples on day 70 was 4 times higher than that in the samples on day 20. The Principal Component Analysis (PCA) verified a clear separation of the stomach oil samples in two groups, according to the day of sampling. The results obtained confirm the role of FAs analysis of stomach oil to understand the ecology and breeding behaviour of C. diomedea, highlighting a resemblance with signatures recorded in marine organisms of Linosa Island.