There were investigated the level of common lipids and the ratio of their individual classes – phospholipids, monoacylglycerols, diacylglycerols and triacylglycerols, free and esterified cholesterol, unesterified fatty acids in the 6–8 weeks old quails pancreas (the period of laying eggs formation) under condition of nitrates influence and feeding of mixed fodder with the addition of amaranth seeds.
The body's response to nitrate loading and the feeding of amaranth seeds was evaluated according to biochemical parameters in the pancreas, one of the largest glands in the body. For laboratory experiments there were used quails by Pharaon breed. Quails were divided into three groups of 60 heads in each, fed the standard feed, access to feed and water was free. The birds of the first group served as control, the birds of the second group, in order to model the stress state, water was dispensed with sodium nitrate at a dose of 0.5 g / kg of body weight. Birds of the third group were fed a mixed fodder with seeds of amaranth at the rate of 10 % of the mass of mixed fodder on the background of nitrate loading. Decapitation was performed under etheric anesthesia and the pancreas was taken from a 6-week-old birds (the beginning of the laying eggs period). In the extract of the pancreas, the content of total lipids and their individual classes were were srudied and expressed as a percentage of the total number of lipids. For identification of lipids on a chromatographic plate, the standard preparations of individual lipids from Sigma (USA) were used.
The obtained results indicate that nitrate loading leads to a decrease in the common lipids content in the quail pancreas tissues. Thus, their number in the 6-week-old age is reduced by 37.0 % (p<0.05), and in the 8-week-old period – by 22.7 % (p<0.05) compared with the control group. Lipids perform structural and energy functions, as well as determine the important role for the adaptation of the organism to stress factors. Due to the long nitrate influence and due to the unequal functionality of the antioxidant systems of the body, protective mechanisms are violated, which leads to the occurrence of pathological processes. At the same time there are certain changes in the ratio of individual classes of lipids. In particular, the content of unesterified fatty acids (UFA) in 6-week-old poultry decreases by 13.3 % (p<0.05) and 8-week –12.4 % (p<0.05) compared to control. The level of UFA in tissues and serum is related to the energy supply of the bird organism and characterizes the activity of lipolysis processes and their mobilization from fat depots. The decrease in the tissues of the number of UFA indicates their intensive use in energy processes.
Feeding of mixed fodder with seeds of amaranth against the background of nitrate influence causes changes in the total content of lipids and the ratio of their individual classes in pancreatic tissue compared with control and 2nd group. Thus the poultry, which was fed with mixed amaranth seeds alongside with nitrate influence, had increasing of total lipids content in comparison with the 2nd group in the 6-week old age in 2,0 times (p<0,05), in the 8-week-old – in 2,2 times (p<0,001) and in comparison with the control group at 8-year-old in 1,5 times (p<0,05). At the same time, the content of mono- and diacylglycerols is reduced by 15.3–20.9 % (p<0.05), while triacylglycerols increases by 45.5 % relative to the control (p<0.05). Feeding amaranth seeds to quail results in an increase in the content of esters of cholesterol in the 8-week-old age by 1.3 times (p<0.05) compared to the second group and, as compared with control, their content increases in the pancreas of 6–8 weeks old birds by 20,9–36.7 % (p<0.05). These patterns indicate that inhibition of lipolysis and accumulation of reserve lipids in pancreatic tissue is inhibited. The increase in the number of cholesterol esters indicates their active use in the bird organism as a result of changes in the processes of esterification and hydrolysis of cholesterol under the influence of biologically active substances of the seeds of amaranth, in particular squalene. It can be assumed that when entering the body, amaranth seed squalene initially leads to an increase in the content of cholesterol in the pancreas, since it is a precursor to the synthesis of cholesterol. Accordingly, the increase of cholesterol content activates the enzyme acyl-CoA-cholesterol-acyltransferase, while the content of cholesterol esters begins to increase. It is worth noting that the steroid core in cholesterol esters is more resistant to oxidation and, possibly, for this reason, the cell is better stored cholesterol in the form of esters. Amaranth bird feeding on the background of nitrate loading prevents the decrease of the total lipids content and contributes to the accumulation of reserve lipids in the pancreas. It can be explained by the content of amaranth polyunsaturated fatty acids, which, along with vitamins and trace elements, regulate lipid metabolism in the bird organism.
Thus, nitrate influence leads to a decrease in the total content of lipids in pancreatic tissue of 6–8 weeks-old quails and a decrease in the amount of unesterified fatty acids, which indicates the intensive their using in energy processes. Feeding of poultry with mixed fodder with amaranth seeds during the period of laying eggs formation perion on the background of nitrate influence contributes to increase of total lipids content to the level of control group. Along with this, changes in the ratio of individual classes of lipids have been established, which are manifested by a decrease in the content of mono- and diacylglycerols and an increase in the content of cholesterol esters.
Key words: phospholipids, monoacylglycerols, diacylglycerols, triacylglycerols, free cholesterol, cholesterol esters, unesterified fatty acids, pancreas, nitrates, quails, amaranth.
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