Abstract
Simple SummaryAn experiment to determine the effect of sheep breed on subcutaneous fatty acid composition was carried out at the Butalcura Research Station, Chiloé, Chile. To this end, two breeds of lambs were challenged to graze a typical, naturalized pasture of the Chiloé Archipelago, Chile, from 60 d to 120 d after birth. The animals were sacrificed to collect samples from subcutaneous fat (SCF) from the back, and tail fat (TF) to determine the effect of breed on transcriptional expression of lipogenic enzymes and fatty acid profile in these two fat depots. The results showed that although mRNA expression of enzymes was similar in both breeds, there were differences in certain protein levels in the SCF, partially related with the fatty acid profiles, thus affecting the selection of lamb breed either for human consumption or experimental purposes.This experiment was carried out to determine the effect of breed on mRNA and protein expression levels of lipogenic enzymes acetyl-CoA carboxylase α (ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase 1 (SCD1) plus sterol regulatory element binding transcription factor 1c (SREBP1c) in the subcutaneous fat (SCF) from the back of the animal, and tail fat (TF) of both Chilota and Suffolk Down lambs grazing Calafatal. Eight Chilota and six Suffolk Down 2-month-old male lambs were allocated to graze a “Calafatal”, a typical secondary succession of Chiloé Archipelago, Chile. After 62 d, lambs were slaughtered according to Chile’s meat industry standards. Fatty acid profile, RT-qPCR, and Western blot analyses from SCF and TF samples were performed. Although the mRNA expression levels of ACC, FAS, SCD1 and SREBP1c in SCF did not differ significantly between breeds (p > 0.05), a trend to higher mRNA expression of FAS and SREBP1c in TF from Chilota lambs was observed (p = 0.06). On the other hand, FAS levels in SCF were higher in Chilota than in Suffolk Down lambs (p < 0.02), although Suffolk Down showed higher fat contents and saturated fatty acid (SFA) proportions than Chilota lambs (p < 0.01). The FAS protein expression in TF was similar in both breeds (p > 0.05). Although the fat content was higher in Suffolk Down than in Chilota lambs (p < 0.01), the SFA proportions were similar in both breeds. Finally, it can be concluded that although mRNA expression of enzymes was similar in both breeds, there were differences in some protein levels in the SCF, partially related with the fatty acid profiles, thus affecting the selection of lamb breed either for human consumption or experimental purposes.
Highlights
Chilota, a sheep breed present only in Chiloé Archipelago, Chile, is the product of an intensive genetic differentiation and environmental adaptation process [1], acquiring some unique physical and functional characteristics which have allowed it to be recognized it as a new breed of sheep [2], and nowadays, it constitutes one of the last remnants of Iberian genetic traits without any selection.After an adaptive process of this type, a high rusticity, of health, and concerning feed intake [3], is expected
Unlike feeding concentrates, a diet based on forage increases the n-3 polyunsaturated fatty acids (n-3 PUFA) proportions in the meat [5,7,8,9], improving food quality intended for human consumption [10]
The objective of this study was to evaluate the effect of lamb breed on mRNA and protein expression levels of some key lipogenic enzymes, such as acetyl-CoA carboxylase α (ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase 1 (SCD1), and sterol regulatory element binding transcription factor 1 (SREBP1c) and its final effect on the fatty acid profile in subcutaneous fat (SCF) and tail fat (TF) from Chilota and Suffolk Down lambs fed on Calafatal
Summary
A sheep breed present only in Chiloé Archipelago, Chile, is the product of an intensive genetic differentiation and environmental adaptation process [1], acquiring some unique physical and functional characteristics which have allowed it to be recognized it as a new breed of sheep [2], and nowadays, it constitutes one of the last remnants of Iberian genetic traits without any selection.After an adaptive process of this type, a high rusticity, of health, and concerning feed intake [3], is expected. Unlike feeding concentrates, a diet based on forage increases the n-3 polyunsaturated fatty acids (n-3 PUFA) proportions in the meat [5,7,8,9], improving food quality intended for human consumption [10]. Changes in the fatty acid profile, related to increased PUFA proportions, could be explained by changes in the expression levels of some genes associated with fatty acid metabolism [11,12,13]. In this regard, a tissue-specific response has been described in both muscle and adipose tissues [6]
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