Jerzy Lechowski
Ocena efektywności dodatku kwasu askorbinowego do paszy na cechy reprodukcyjne młodych loszek i knurów inseminacyjnych oraz właściwości fizyczne i chemiczne mięsa tuczników
zeszyt 334, ss. 79
The present researches evaluated the effect of dietary ascorbic acid supplement on the performance parameters of young gilts and insemination boars as well as physical and chemical properties of fatteners’ meat. The experimental pig group(gilt fatteners, breeding gilts and reproductive boars) was administered vitamin C at a dose of 2, 5 g/unit for 30 days,  pregnant primiparous  gilts – for 6 weeks pre partum, whereas  a part of gilt fatteners – for the same length of time prior to slaughter. All the pigs from the control groups were fed full ration diets without a vit. C content. Having reached the desired body weight, the fatteners were slaughtered and their organs and tissues sampled for the examination of an ascorbic acid level and activity of L-gulono-gamma-lactone oxidase enzyme. Then there was established a synthesis level of ascorbic acid and L-gulono-gamma-lactone oxidase enzyme activity that contributed to this acid synthesis in some chosen tissues and organs of the fatteners. After slaughter, the samples of liver, kidneys, lungs, heart, loin, ham and blood were collected to determine the analyzed compounds. There were also sampled the tissues of ham meat and loin to establish pH1 and pH2 and a glycogen content as well as to evaluate a free water content (%), reemission (W) and meat lightness and color. The reproductive organs of the unfertilized fattener gilts of PLW and pulawska breed were assessed after the third estrus, immediately after slaughter on the basis of the following criteria: total weight of reproductive organs, uterus weight, ovary weight (left and right), length of uteral horns (left and right), number of ovarian follicles and luteal bodies. The breeding gilts of PLW and pulawska breed with dietary vit. C supplementation had blood collected from the marginal ear vein and 17beta-estradiol and progesterone concentration determined in blood serum. At the same time, blood was taken from the control group gilts. The boars of PL, PLW, Hampshire, pietrain breeds (maintained in the Artificial Insemination Station) had ejaculates collected that constituted the control group samples. After boar organism was saturated with vitamin C, ejaculates were collected to make up the experimental group samples. The analyses revealed the differences in the ascorbic acid synthesis not only within the kind of organs and tissues but between each pig breed as well. The research results clearly indicate that the genetic differences between the fattener breed under study have affected a level of vitamin C synthesis in pig organs and tissues. The highest level of ascorbic acid synthesis was observed in the pulawska breed followed by PLW and slightly lower in Hampshire, whereas pietrain appeared to be the lowest. It is implicated by  differentiated activity of microsomal enzyme L-gulono-gamma-lactone oxidase which is a key enzyme in the last stage of ascorbic acid synthesis in each breed. The highest ascorbic acid content and synthesis among the organs and tissues of all the fatteners of the analyzed breeds was determined in the liver, then kidneys, lungs, heart, loin and ham. While the lowest values of the studied compounds were detected in muscle tissue in ham and loin. The present investigations showed that a dietary additive of vitamin C increased this vitamin saturation in the organs and tisues. There was also proven the growth of activity of L-gulono-gamma-lactone oxidase participating in the final stage of L-gulono-gamma-lactone conversion into ascorbic acid during the cycle synthesis on 14th day after the vitamin C supply cessation. That may confirm a positive impact of pig saturation with this vitamin on the mechanisms associated with the acid autosynthesis. Besides, vitamin C was shown to slow down a decline of pH1 and pH2 of ham and loin meat after slaughter which was manifested by their higher values in the experimental group compared to control. A percentage of free water content and reemission (W) as well as meat lightness fell. The changes resulted in the stability of natural meat color intensity. Whereas the changes in the experimental group meat occurred as a consequence of the impaired glycogenolysis and glycolysis processes confirmed by partial inhibition of glycogen breakdown in meat and liver as well as a decrease of lactic acid level in fatteners’ blood. However, no changes in the basic chemical composition of meat were recorded. The research results indicate a statistically significant increase of the total weight of reproductive organs of pulawska and PLW breed of gilts subjected to vitamin C activity. The biometric measurements of the reproductive organs revealed a significant increase of ovary and uterus weight with concurrent elongation of its horns. The state of the ovary development was similar. A number of ovary follicles and luteal bodies appeared to be higher. The obtained results varied for each breed. Vitamin C employment also caused an increase of synthesis of both 17beta-estradiol and progesterone and the level recorded was slightly different, being breed-depenedent. Higher growth of 17beta-estradiol and progesterone was recorded in pulawska breed. In pregnant primiparous gilts of both breeds supplied with vit. C, after parturition there was noted an increase of protein, dry mass, IgG immunoglobulins amount as well as vitamin C content in colostrums and milk. The changes reduced a mortality rate, increased number of reared piglets and their body weight gains and mass. In the present studies, vitamin C administered to boars has also affected ejaculate quality. Beside increased ejaculate volume, there also noted increased sperm cell count in total ejaculate as well as elevated percentage of spermatozoa showing forward motility and heightened number of doses. A value of these changes was subject to a boar breed and  likely to emerge from the genetic differences between the breeds. Stimulation of alkaline phosphatase activity by vitamin C caused more intensive  forward motility of sperm cells through supply of energy contained in fructose produced more abundantly due to the breakdown of phosphohexose present in sperm or probably through a decreasing level of lactic acid displayed by a higher sperm cell pH recorded. The study results obtained point to purposefulness of dietary vitamin C supplementation to swine diets.