Nutritive characterization of purslane accessions as influenced by planting date.

The uniqueness of purslane (Portulaca spp.) as the richest vegetable source of omega-3 (omega-3) fatty acids is well documented. However, purslane has not been domesticated or fully evaluated for its nutritive value. The objective of this study was to determine the influence of planting date on chemical composition of purslane accessions. Eight accessions from different geographical locations were planted 12 days apart, and whole plants harvested at full bloom. Chemical analysis (DM basis) of leaves showed significant differences among varieties for all the characteristics measured. Accession by planting date interaction influenced (p <0.05) levels of crude protein, total lipids, and carbohydrate contents. Wild Greek accession had the highest, while a Beltsville (Maryland) wild type had the lowest crude protein content (27.1 vs 20.5%) at the second planting date. Crude protein, lipid and ash levels were most influenced (p <0.05) by planting date. Total lipids varied from 4.0-5.8% and 3.7-5.1% for the first and second planting dates, respectively. Selected fatty acid content indicated significantly (p <0.05) higher levels of 18: 2omega6, and 18: 3omega3 in the Dutch Garden accession compared with other varieties. The Egyptian wild accession had the lowest level of 18: 3omega3. The ratio of omega3 to omega6 acids, which ranged from 5.5 to 22.3 indicated a high nutritive value of purslane compared to other oil crops such as soybeans and perrilla. The high levels of protein in purslane compete with those of other commercially important vegetable crops. The study shows that, in spite of its genetic diversity, purslane remains one of the most abundant terrestrial vegetable sources of Omega-3 fatty acids and other essential nutrients potentially beneficial for humans as well as animals.

Postnatal response of liver and skeletal muscle in pigs from gestationally fasted gilts.

Fifteen pregnant crossbred gilts were randomly assigned to one of three treatments (0, 7 or 14-day fast) to study the response of liver and skeletal muscles in the progeny to preparturent maternal fasting. The control group was fed 1.82 kg of diet/day throughout gestation, 7-day and 14-day fasted groups were taken off feed on days 107 and 100 of gestation, respectively. Water and trace mineral salts were provided ad libitum. Body weight, liver weight, and gastrocnemius muscle weight at birth and at 49-day of age were not affected by the treatments (P greater than .05). Total liver DNA was depressed (P less than .025) at birth in the progenies of fasted gilts. Total gastrocnemius muscle DNA was lower at birth in the 14-day (P less than .05) and 7-day (P less than .10) fasted progenies. Protein, RNA, protein/DNA, and RNA/DNA ratios in the liver and muscle of pigs at birth were not altered by maternal treatments. At 49-day of age, total muscle DNA were similar among the treatment groups, however, the livers of pigs from fasted dams had elevated (P less than .05) total DNA content as well as DNA concentrations. No differences were noted in muscle and liver protein, RNA, RNA/DNA, and protein/DNA ratios. The results indicate that complete feed-deprivation from 7 to 14 days before parturition in gilts did not cause a permanent growth retardation in progenies and appeared to stimulate liver DNA synthesis.

Effect of streptozotocin-induced diabetes in primiparous swine on subsequent reproductive performance.

A follow-up study was conducted to determine the effects of streptozotocin-diabetes during the first parity on subsequent reproductive performance of sows. Only in the first parity, two doses of streptozotocin (50 and 100 mg/kg body weight) were administered to two groups of pregnant gilts at 80 d of gestation; a third group of gilts served as a control. Second-parity reproductive performance showed that gestation length, placental weight, mean birth weight of the litter, litter size and number of pigs born alive were not affected (P greater than .05) by maternal diabetes. Maternal serum glucose and fructose were greater (P less than .01) in high-dose sows than in the low-dose and the control dams. Serum free fatty acids (FFA) were higher (P less than .05) in high-dose dams than in control dams at d-1 and d 112 of gestation; no differences were observed between the high-dose and the low-dose during the same period. Liver and kidney weight, as well as DNA and RNA content, were greater (P less than .01) in pigs from high-dose dams than in those of the other treatments. Liver protein was elevated (P less than .01) in the progeny of high-dose dams. Dry matter and percent lipid were higher (P less than .05 and P less than .01, respectively), in pigs from high-dose sows than those from other treatment. Serum glucose, fructose and FFA of piglets were not affected by previous treatment of the dam.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of maternal streptozotocin-diabetes on fetal growth, energy reserves and body composition of newborn pigs.

Two doses of Streptozotocin (50 and 100 mg/kg body weight) were administered to two groups of pregnant gilts at d 80 of gestation to determine the influence of two levels of maternal diabetes on the gilts, their developing progenies and the body composition of the pigs. All the experimental animals received 1.82 kg of gestation diet/day throughout gestation. Serum glucose concentration increased to hyperglycemic levels in low-dose and high-dose groups; insulin concentrations decreased (P less than .01) in the high-dose, but not in the low-dose group (P greater than .05). Maternal free fatty acids (FFA) increased (P less than .05) in both treatment groups when compared with the control. However, birth weight of the litter and litter size were not affected. The liver weight increased (P less than .01) in the progeny of high-dose but not the low-dose group. Total liver DNA and RNA were not altered by the treatments, however; total liver protein and protein:DNA ratio increased (P less than .01) in the progeny of high-dose gilts. Pigs from high-dose and low-dose groups showed increases (P less than .01) in liver glycogen concentrations and percentage liver lipid. Body chemical composition data showed increases in percentage dry matter and percentage lipid (P less than .05 and P less than .01, respectively) in the progeny of high-dose but not in the low-dose group. It was concluded that streptozotocin administered to gestating gilts increased the maternal nutrient supply to the developing pigs, which resulted in higher energy status of the pigs at birth.

Cellular development of liver and skeletal muscles and body composition of pigs from gestationally starved sows.

Liver and skeletal muscle development and changes in body composition were studied in pigs from cross-bred sows subjected to starvation (allowed water and trace mineral salt) during the third trimester of gestation. Two groups of sows were taken off feed on days 93 (21-day) and 107 (7-day) of gestation respectively; a third group fed 1.82 kg of diet per day served as control. The pigs sacrificed at birth, were used to determine liver and skeletal muscle DNA, RNA and protein and body composition. There were no significant differences (P greater than .05) in body weight between the treated groups and the control. Liver weight was depressed in the progeny of 21-day and 7-day starvation groups (P less than .05). Liver cellular DNA was decreased (P less than .05) in the treated animals, RNA and protein content remained unchanged. The skeletal muscles studied responded differently to the treatment imposed; semitendinosus muscle weight, muscle DNA and RNA did not differ among treatments; whereas, gastrocnemius muscle weight, muscle DNA and RNA were significantly lower in the progeny of treated sows (P less than .05, P less than .01 and P less than .05 respectively). Muscle and liver protein content, RNA/DNA, and protein/DNA ratios were not affected by treatments. Body composition analysis showed no differences in per cent dry matter, lipid, ash and protein content. The results suggest that liver and gastrocnemius muscles were adversely affected by prenatal nutritional deficiency imposed while semitendinosus muscles remained unchanged. The differential response of skeletal muscles to prenatal nutritional deficiency indicated a need to study more than a single muscle in similar experiments designed to investigate muscle response. The lack of differences in body composition analysis showed that improved survival of newborn pigs previously reported can be achieved without changes in fetal chemical body composition.

Effects of maternal starvation on some blood metabolites, liver glycogen, birth weight and survival of piglets.

Pregnant crossbred sows were assigned to three treatments during the third trimester of gestation for an evaluation of the effects of maternal starvation on fetal development and piglet survival. Two groups of sows were taken off feed (water and trace mineralized salt only) on days 93 and 107 of gestation, respectively; the third group was fed 1.82 kg of complete sow diet/day and served as the control. Litter size, gestation length and pig birth weight in the 7-day and 21-day starvation groups were not different from those in the control group (P less than .05). Liver weight was depressed (P greater than .05) among the 7-day and 21-day progeny. However, liver glycogen concentrations and total liver glycogen were unaffected. Maternal blood glucose decreased to a fasting but steady level, while free fatty acid (FFA) increased in the two starved groups. Blood glucose and FFA at birth were similar for all treatment groups; however, FFA increased in the progeny of sows in the 7-day (P greater than .05) and 21-day (P greater than .01) starvation groups at 48 hr of age. Blood glucose at 48 hr did not vary (P less than .05), but the control progeny showed a faster glucose utilization, suggesting a greater dependence on carbohydrate metabolism than in the progeny of starved dams. Survival rate at 72 hr of age was higher among 21-day (43.8%) and 7-day (37.5%) progeny than among control progeny (8.5%). The increased plasma FFA level observed with fasting in the progeny of starved dams might indicate a shift toward lipid metabolism, which would account for the improved survival observed among the progeny of treated dams.

The effects of maternal alloxan diabetes on body composition, liver enzymes and metabolism and serum metabolites and hormones of fetal pigs.

Pregnant Yorkshire gilts were allotted to three treatment groups during the third trimester of gestation. One group was injected with alloxan at 70 days of gestation; the second group was injected daily with protamine zinc insulin beginning at 80 days, and the third group received saline injections serving as controls. At 112 days of gestation, the fetuses were delivered alive by hysterectomy, and utilized for analyses. Body composition data indicated a significant increase in percent fat in the diabetic progeny. Liver lipogenic enzyme profiles did not indicate a significant change in activity to account for the increased carcass lipid. In fact, liver lipogenesis from labelled pyruvate was depressed in livers of diabetic progeny. Insulin levels were low in all the groups suggesting that hyperglycemia observed in the progeny of diabetic gilts had little insulin stimulatory action on the fetal pancreatic B-cells. Fructose levels were significantly increased in the progeny of diabetic gilts. Insulin injections during pregnancy did not influence fetal body weight or body compositions. The mechanisms(s) of increased lipid deposition in infants of diabetic mothers (IDM) may involve de novo fatty acid synthesis by adipose cell or direct incorporation of maternal fatty acids into fetal adipose cells.

Muscle and adipose cell development in mice selected for postweaning growth rate.

Genetic selection for postweaning growth rate between 3 and 6 weeks of age resulted in significant changes in body weight, semimembranosus muscle weight, and epididymal fat pad weights. Body weights at 15 weeks of age ranged from 24.9 gm for the Low line (slow growth) mice and 59.4 gm for the High line mice (rapid growth). Total muscle DNA content was decreased in Low line mice and increased in High line mice when compared to Control mice (random bred). RNA to DNA and protein to DNA ratios were not significantly affected by growth rate selection pressure. Selection for high or low growth rate appeared to affect the development of muscle by altering the amount of DNA synthesized, suggesting that growth hormone status was altered by this type of selection. Adipose cell number was reduced in the Low line and increased in the High line when compared to Control mice. Adipose cell size was increased in High line mice when compared to Low and Control lines. The role of adipose cell development in supporting growth selection success is suggested.

Cellular characteristics of skeletal muscle in selected strains of pigs and mice and the unselected controls.

Skeletal muscle growth of swine differing in rate of growth and muscularity was studied by analysis of DNA, RNA, and protein in the semitendinosus muscle of fast growing domestic lean pigs (Yorkshire) and the slow-growing feral obese pigs (Ossabaw). Both lean and obese strains were fed ad libitum corn and soybean mean diet containing 14% protein. The pigs were slaughtered at 6 months of age. The Yorkshire pig had significantly greater body and muscle weights (P less than 0.005) Total DNA, RNA, and protein in semitendinosus muscles were significantly greater in the Yorkshire pigs (P less than 0.005). RNA/DNA and protein/DNA ratios were significantly different between the Yorkshire and Ossabaw pigs. These data suggest that the greater muscle growth in the Yorkshire pigs is achieved by greater cell numbers and size. The response of skeletal muscle cells and fiber characteristics to selection was studied in two strains of mice by analysis of DNA, RNA, and histological measurement of muscle fibers. Both strains were fed ad libitum on laboratory rat chow diet. They were sacrificed at 12 months of age. Leg muscle DNA and RNA were significantly greater in the mice selected for rapid growth rate as compared to the control (P less than 0.005 and P less than .10, respectively). Measurements of the semimembranosus muscle reveal that the growth strain had significantly greater muscle weight (P less than .01) and muscle length (P less than 0.005). Histological measurements of the same muscle showed that the growth strain had significantly greater fiber number (P less than 0.005) and larger fiber size (P less than 0.005) than the controls. It would appear that the greater muscle cellularity (DNA) in growth strain mice is accompanied by greater muscle length, fiber number, and fiber diameter.