Influence of dietary conjugated linoleic acids (CLA) and age at slaughtering on meat quality and intramuscular collagen in rabbits

Comparison of lauric acid and 12-hydroxylauric acid in the alleviation of drought stress in peach (Prunus persica (L.) Batsch)

Water shortage is a key factor that can restrict peach tree growth. Plants produce fatty acids and the fatty acid derivatives lauric acid (LA) and 12-hydroxylauric acid (LA-OH), which are involved in abiotic stress responses, but the underlying stress response mechanisms remain unclear. In this study, physiological examination revealed that in Prunus persica (L.) Batsch, pretreatment with 50 ppm LA-OH and LA reduced drought stress, efficiently maintained the leaf relative water content, and controlled the relative conductivity increase. Under drought stress, LA-OH and LA treatments prevented the degradation of photosynthetic pigments, increased the degree of leaf stomatal opening and enhanced the net photosynthetic rate. Compared with drought stress, LA-OH and LA treatment effectively increased the net photosynthetic rate by 204.55% and 115.91%, respectively, while increasing the Fv/Fm by 2.75% and 7.75%, respectively, but NPQ decreased by 7.67% and 37.54%, respectively. In addition, the level of reactive oxygen species increased under drought stress. The content of O₂ ^- in LA-OH and LA treatment decreased by 12.91% and 11.24% compared to CK-D, respectively, and the content of H₂O₂ decreased by 13.73% and 19.94%, respectively. At the same time, the content of malondialdehyde (MDA) decreased by 55.56% and 58.48%, respectively. We believe that the main reason is that LA-OH and LA treatment have improved the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). The application of exogenous LA increased the levels of soluble sugars, soluble proteins, proline and free amino acids under drought stress, and maintained the osmotic balance of cells. Compared with CK-D treatment, it increased by 24.11%, 16.89%, 29.3% and 15.04%, respectively. At the same time, the application of exogenous LA-OH also obtained similar results. In conclusion, exogenous LA-OH and LA can alleviate the damage to peach seedlings caused by drought stress by enhancing the photosynthetic and antioxidant capacities, increasing the activities of protective enzymes and regulating the contents of osmotic regulators, but the molecular mechanism is still in need of further exploration.

Growth performance, meat quality and Fatty Acid metabolism response of growing meat rabbits to dietary linoleic Acid

An experiment was conducted to determine the effects of different amounts of dietary linoleic acid (LA) on growth performance, serum biochemical traits, meat quality, fatty acids composition of muscle and liver, acetyl-CoA carboxylase (ACC) and carnitine palmitoyl transferase 1 (CPT 1) mRNA expression in the liver of 9 wks old to 13 wks old growing meat rabbits. One hundred and fifty 9 wks old meat rabbits were allocated to individual cages and randomly divided into five groups. Animals in each group were fed with a diet with the following LA addition concentrations: 0, 3, 6, 9 and 12 g/kg diet (as-fed basis) and LA concentrations were 0.84, 1.21, 1.34, 1.61 and 1.80% in the diet, respectively. The results showed as follows: the dietary LA levels significantly affected muscle color of LL included a* and b* of experimental rabbits (p<0.05). The linear effect of LA on serum high density lipoprotein cholesterol was obtained (p = 0.0119). The saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) contents of LL decreased and the polyunsaturated fatty acids (PUFAs) content of LL increased with dietary LA increase (p<0.0001). The PUFA n-6 content and PUFA n-3 content in the LL was significantly affected by the dietary LA levels (p<0.01, p<0.05). The MUFAs content in the liver decreased and the PUFAs contents in the liver increased with dietary LA increase (p<0.0001). The PUFA n-6 content and the PUFA n-6/n-3 ratio in the liver increased and PUFA n-3 content in the liver decreased with dietary LA increase (p<0.01). The linear effect of LA on CPT 1 mRNA expression in the liver was obtained (p = 0.0081). In summary, dietary LA addition had significant effects on liver and muscle fatty acid composition (increased PUFAs) of 9 wks old to 13 wks old growing meat rabbits, but had little effects on growth performance, meat physical traits and mRNA expression of liver relative enzyme of experimental rabbits.

The role of rabbit meat as functional food

Increasing consumer knowledge of the link between diet and health has raised the awareness and demand for functional food ingredients. Meat and its derivatives may be considered functional foods to the extent that they contain numerous compounds thought to be functional. This review will attempt to outline the excellent nutritional and dietetic properties of rabbit meat and offer an overview of the studies performed on the strategies adopted to improve the functional value of rabbit meat. Dietary manipulation has been seen to be very effective in increasing the levels of essential FA, EPA, DHA, CLA, branched chain FA, vitamin E, and selenium in rabbit meat. Dietary fortification with vitamin E or natural products such as oregano essential oil, chia seed oil, and Spirulina platensis microalga seem promising in improving the oxidative stability of rabbit meat while also adding functional ingredients.

Dietary conjugated linoleic acids decrease leptin in porcine adipose tissue

We investigated the effects of dietary conjugated linoleic acids (CLA) on white adipose tissue (WAT) in heavy pigs. Twelve pigs were assigned to 1 of 2 groups supplemented with either 0 or 0.75% of a CLA preparation (isomeric mixture) and were slaughtered at 159 +/- 2.3 kg live weight. Their subcutaneous WAT was analyzed by both chemical and microanatomical methods. The WAT of CLA-fed pigs tended to have a higher protein content (P = 0.064) and smaller adipocytes (P = 0.053) than that of control (CTR) pigs. The number of proliferating preadipocytes tended to be greater (P = 0.076) in pigs fed CLA, whereas the number of apoptotic adipocytes was greater (P < 0.01) than in CTR pig. Immunohistochemistry revealed that leptin (Ob) expression was lower (P = 0.048) in adipocytes from treated pigs and Western blot quantification of Ob revealed lower levels (P < 0.05) in CLA-fed pigs. The Ob receptor was not affected by dietary CLA supplementation. Tyrosine hydroxylase activity was higher (P < 0.001) in WAT of CLA fed-pigs than in CTR. It is conceivable that the increased noradrenergic activity due to dietary CLA decreases the Ob expression, although it does not diminish the lipid content of WAT, at least in heavy pigs. This article describes the interaction between CLA and Ob in the WAT of heavy pigs and we hypothesize that there is an increased noradrenergic stimulation of lipolysis directly in the target tissue.

Performance and tissue fatty acid profiles in veal calves fed diets supplemented with conjugated linoleic acids

Three groups of six calves each were fed a milk replacer at 0.8 kg and a starter concentrate ad libitum. Calves of the control group received the basal diet supplemented with rapeseed oil at 10 g per kg of feed solids. Calves of treatment groups were fed diets supplemented with a synthetically produced oil containing 62.3% methyl esters of CLA. The CLA-oil was added to milk at expense of rapeseed oil and fed at 5 and 10 g x kg(-1) feed solids for 63 days. Calves were slaughtered at 115 days of age. There was no significant effect of CLA on growth, intake of starter, feed conversion, chemical composition of meat and its oxidative stability. Dietary supplementation with CLA at 10 g x kg(-1) significantly increased CLA content in m. longissimus dorsi (MLD) from 5.6 to 19.3 mg x 100 g(-1), in liver from 13.1 to 68.8 mg x 100 g(-1), and in perirenal fat from 0.37 to 3.17 g x 100 g(-1). Dietary CLA decreased the ratio of cis-9, trans-11 and trans-10, cis-12 isomers of CLA in tissues, concentration of monounsaturated fatty acids in the MLD and fat, as well as the concentration of fatty acids with 20 and 22 carbon atoms. It can be concluded that in veal calves unprotected CLA apparently escaped ruminal hydrogenation, but was preferentially incorporated into depot fat.

Partial replacement of pork fat by conjugated linoleic acid and/or olive oil in liver pâtés: Effect on physicochemical characteristics and oxidative stability

The effect of replacing pork fat in liver pâtés by an enriched conjugated linoleic acid oil (CLA-pâté), olive oil (OO-pâté), or the combination of both type of oils (CLA+OO-pâté) on the fatty acid profile, lipid oxidative stability, consistency and emulsion stability was studied and compared with a traditional liver pâté (C-pâté). Pâtés were analyzed at days 1, 6, 21 and 71 of refrigerated storage (4°C). A enrichment in CLA was attained in CLA-pâté and CLA+OO-pâté. CLA-pâtés had the highest content in polyunsaturated fatty acids (PUFA) (p<0.05) due to their content in CLA. A lower content in saturated fatty acids was achieved when using OO or CLA in pâtés (p<0.05). OO-pâtés showed the highest levels of monounsaturated fatty acids (MUFA) (p<0.05). No changes in the fatty acid profile and in lipid oxidation (mg malondialdehyde per kg of sample) throughout the storage of the products were found. Lower consistency and emulsion stability were obtained when using CLA or OO in the formulation. Consistency values (in N/cm(2)) tended to increase and emulsion stability to decrease throughout the storage in CLA or OO enriched pâtés.