Dietary fatty acids and the time elapsed from their intake are related to their composition in rat submandibular gland and salivary flow rates

Abstract

The aim of this study was to analyze the influence of dietary fatty acids (FAs) and the time elapsed from their intake on FA tissue profile of rat submandibular gland (SG) and on its salivary flow rate (SFR). Do dietary FAs depending on the intake time modify their profile in SG and consequently the SFR? Thirty-six adult male Wistar rats were fed on control diet (corn oil, CD, 18:2 n-6 FA) for 7days and then divided into CD and two groups with replacement of corn oil by olive (OD, 18:1 n-9 FA) or chia (ChD, 18:3 n-3 FA) oils (1 and 30day intake). Submandibular ducts were canalized to collect saliva for 20min (μL/min). SG were examined (optical/electron microscopy; ImageJ 1.48 software). SFR values were 6.18 ± 0.34 (CD1), 6.04 ± 0.31 (OD1), and 6.00 ± 0.50 (ChD1) (p > 0.05). At 30-day intake, higher SFR values in ChD (7.82 ± 0.7) with respect to CD (4.68 ± 0.44; p < 0.001) and OD (6.08 ± 0.2; p = 0.038) were found. ChD30 showed a higher serous acinous area percentage than CD30 and OD30, whereas mucous acinous density was greater in CD30 than in OD30 and ChD30 (p < 0.05). α-Linolenic (ALA) and eicosapentaenoic and docosahexaenoic acid levels were only detected in SG of ChD30, while arachidonic acid was lower in this group as compared with CD30 and OD30 (p < 0.05). SG FA composition and its SFR appear to be modulated by dietary FAs and the time elapsed from their consumption. SFR is highest with n-3 ALA-rich ChD at 30-day intake. Diet could contribute to improve secretory dysfunctions.