Liver lipid accumulation and performance of hens as affected by cage density and initial body weight

Hens housed in individual cages (25 46 cm.) laid significantly more eggs, consumed significantly more feed and had significantly larger livers with a higher lipid content than hens housed three to a cage in two experiments. Body weight gain was significantly higher for individually housed birds in experiment 1, but not in experiment 2. No difference was observed in mean egg weight or kg. feed per dozen eggs. In experiment 2 hens housed two to a cage laid slightly fewer eggs and accumulated slightly less liver fat but the differences were not significantly different fromthose housed individually. Hens socially dominant in three bird pens had higher liver fat accumulation than hens lower on the peck order but liver fat accumulation for the dominant hens still averaged less than hens housed either two or one per cage. Comparison of two strains in experiment 1 revealed a significant difference in rate of egg production and feed efficiency but no difference in liver fat accumulation. Pullets placed in four body weight classes prior to the start of the experiment did not differ significantly in liver fat accumulation per unit of body weight or percentof dry matter of the liver at the end of the experiment. Rate of egg production and feed efficiency were also not significantly different among the body weight classes.     

Effects of dietary fat and eggshell cuticle removal on egg water loss and embryo growth in broiler hatching eggs

The effects of dietary fat and eggshell cuticle removal on egg water loss, embryo growth, and hatchability were determined in eggs from broiler breeder hens at different ages. Hens were fed isocaloric diets containing one of three different types and levels of added fat. In addition, eggs were either left intact or washed to remove the eggshell cuticle prior to set. Cuticle removal increased egg water loss between 43 and 62 wk. Cuticle removal increased relative wet embryo weight at Week 52 and relative dry embryo weight at 52 and 62 wk. Furthermore, at 62 wk, diet and day of incubation interacted to affect wet embryo weight, and diet variably affected dry embryo weight. No treatment differences were observed for cumulative hatchability, rate of hatch, and relative yolk sac weight at Day 19 of incubation. It was concluded that cuticle removal and the addition of fat to breeder diets may influence embryonic growth without having any subsequent effects on hatchability.     

Influence of Fusarium-infected corn and F-2 on laying hens

Diets containing either Fusarium-infected corn supplying 25 and 100 p.p.m. of F-2 (zearalenone) or purified F-2 at these levels did not adversely influence the reproductive performance of laying hens. In trial 1, no deleterious effects were observed for 20- and 36-week body weights, age at first egg, egg weight, albumen height, shell deformation, fertility or hatchability when Fusarium-infected corn was fed to 20-week-old pullets for 28 days. Percent hen-day egg production of birds fed Fusarium-infected corn supplying 25 and 100 p.p.m. of F-2 was superior (P less than or equal to 0.5) to egg production of nontreated controls. In trial 2, three replications of ten adult Leghorn hens were evaluated under five dietary treatments: (1) 16.7% protein basal; (2) basal plus Fusarium-infected corn (25 p.p.m. of F-2); (3) basal plus 25 p.p.m. of (purified) F-2; (4) basal plus Fusarium-infected corn (100 p.p.m. of F-2); (5) basal plus 100 p.p.m. of (purified) F-2. Difference between dietary treatments for 14-day pre-treatment, treatment and post-treatment periods were nonsignificant for 42- and 44-week body weights, egg production, egg weights, fertility and hatchability. Body weights of chicks from hens fed F-2 diets were not significantly different from those of chicks from hens fed the basal diet.     

Effects of dietary taurine on egg weight

Two experiments were conducted to determine whether taurine supplementation to laying hens would influence laying performance. In Experiment 1, a total of 120 White Leghorn hens were fed diets supplemented with 0, 0.25, or 0.5% taurine for 5 wk. Egg weight was reduced significantly by supplementing 0.25 and 0.5% taurine; however, taurine did not affect other laying performance variables. In Experiment 2, a total of 240 White Leghorn hens were fed diets supplemented with 0 or 0.5% taurine and 0 or 0.1% methionine for 7 wk. Egg weight was decreased due to supplementing taurine in the diets; however, dietary methionine did not affect egg weight, and there was no interaction between dietary taurine and methionine. These results suggest that dietary taurine has the potential to decrease egg weight without affecting egg production, feed conversion, or body weight.     

Effect of calcium propionate on performance of laying hens

Laying hens kept in individual cages were fed a practical diet supplemented with 0, 0.1, 0.2., 0.4, or 0.8% calcium propionate for a six-week period. Rate of egg production, average egg weight, feed consumption, and body weight change during the experiment were not significantly affected by and dietary treatments. Liver weight, moisture content and fat content were also no significantly affected by dietary treatments. The results show that the performance of normal hens is not changed by calcium propionate supplementation.     

Rapeseed meal glucosinolates: metabolism and effect on performance in laying hens

Two experiments were conducted with Hyline Leghorn hens to study the metabolism and detrimental effects of rapeseed meal (RSM) glucosinolates. Raw Target RSM was force fed to 12 hens which were killed after varying time intervals (15 min., 30 min., 60 min.) and the contents of areas of the digestive tract (crop; proventriculus and gizzard; duodenum and ileum) were analyzed for the presence of hydrolysis products of progoitrin. Nitrile compounds were found to be present in all areas of the digestive tract in much larger relative amounts than was oxazolidinethione. When commercially prepared RSMs of varying glucosinolate content were fed to laying hens at a 50% level of dietary inclusion, high glucosinolate-content RSM depressed egg production (P less than 0.05) more than low glucosinolate-content RSM but did not cause a greater frequency of liver hemorrhage. Histological examination of liver tissues from hens suffering liver hemorrhage revealed a severe reticulolysis.     

Effects of dietary corn and olive oil versus coconut fat on biliary cholesterol secretion in rats

We have studied the effects of dietary corn and olive oil versus coconut fat on bile formation and fluidity of hepatic plasma membranes in rats. After 4 weeks of feeding the purified diets containing 9% (w/w) of the test fats, there was no difference in plasma cholesterol concentration between the dietary groups. The amount of free and esterified cholesterol in the liver was significantly higher in rats fed either corn oil or olive oil as compared with coconut fat. In the rats fed olive oil, but not in those fed corn oil this was associated with lower rates of biliary phospholipid excretion. Bile flow was not differently influenced by the three dietary fats. Hepatic plasma membranes of the rats fed corn or olive oil contained more cholesterol and less phospholipids than those on coconut fat, which was, however, not accompanied by changes in fluidity of the membranes. These results indicate that in rats the type of dietary fat can induce considerable changes in hepatic cholesterol metabolism without affecting plasma cholesterol concentrations, and without consistent effects on biliary cholesterol secretion.     

Net transfer and incorporation of yolk n-3 fatty acids into developing chick embryos

The effect of egg yolk fatty acid composition on the uptake and utilization of essential n-6 and n-3 fatty acids by the developing chick embryo was studied. Eggs were enriched with n-9, n-3, or n-6 fatty acids by incorporating sunflower seed high in oleic acid (C18:1 n-9), flax seed rich in linolenic acid (C18:3 n-3), or sunflower seed high in linoleic acid (C18:2 n-6) into the laying hen diets. Fertile eggs were collected and incubated. The fatty acid composition of eggs and newly hatched chicks were compared. Feeding diets containing flax seed increased (P < .05) total n-3 fatty to 528.4 mg compared with 53.9 and 39.3 mg for eggs from hens fed diets with high oleic acid or regular sunflower seed, respectively. Levels of C18:2 n-6 and monounsaturated fatty acids were higher in eggs from hens fed diets containing regular or high oleic acid sunflower seeds. Dietary fat did not influence the total lipid content of the egg yolk or total lipids of chick tissues. The fatty acid composition of the hatched progeny was significantly altered by egg yolk lipids. However, the percentage incorporation of essential n-6 and n-3 fatty acids into the progeny increased when yolk sources of these fatty acids were low. The developing chick embryo appeared to preferentially take up docosahexaenoic acid and arachidonic acid from the yolk lipids. Evidence also suggests that conversion of C18:2 n-6 and C18:2 n-3 to longer chain n-3 or n-6 fatty acids occurs during the incubation period.     

Update on pediatric heart transplantation. Long-term complications

We have previously observed changes in colon cell proliferation in growing rats fed different levels of dietary fat as beef tallow or corn oil. Here we measured cellular proliferation at 18 and 30 weeks in the colon of rats fed beef tallow or corn oil and treated with the chemical carcinogen azoxymethane. Additionally, we assessed colon cell membrane lipid composition after 18 weeks on the defined diets and tumor incidence at 30 weeks. Dietary fat type and quantity significantly affected colon cell proliferation. Membrane phospholipids and free fatty acids were significantly affected by fat type. Tumor incidence was not affected by diet type. We conclude that dietary fat induces changes in cell membrane lipid composition and proliferation in the colon and these changes may be related to the development of tumors.     

Enrichment of hen eggs with n-3 long-chain fatty acids and evaluation of enriched eggs in humans

Eggs enriched with n-3 polyunsaturated fatty acids (PUFAs) were produced by hens fed diets containing fish oil or a combination of fish and vegetable oils. In a sensory evaluation, 78 untrained volunteers could not distinguish between ordinary and enriched eggs. Storage life was also not significantly different between egg types. A food intake survey of 4 groups of 14 subjects each who consumed 7 eggs/wk for 24 wk showed that intakes of the major dietary components were not significantly different for 4 different egg types. Mean (n = 56) plasma cholesterol and triacylglycerol concentrations were not significantly different at the start and finish of the study. Body weight and HDL concentrations increased during the study (P < 0.05). For the last 2 wk of the experiment (weeks 23-24), mean egg consumption was increased from a total of 14 to a total of 21 eggs, resulting in a small increase in plasma triacylglycerols only. There were no significant differences (P > 0.05) in body weight, blood pressure, or plasma lipid components among treatment groups consuming the 4 different egg types. Blood samples taken after 16 and 22 wk from fasted subjects showed significant increases in eicosapentaenoic acid, docosahexaenoic acid, and total n-3 PUFAs in subjects consuming enriched eggs compared with controls. In addition, the ratio of n-6 to n-3 PUFAs in plasma was significantly reduced from 12.2:1 to 6.5-7.7:1 in subjects consuming enriched eggs compared with controls. Consumption of only one enriched egg daily can contribute substantially to the recommended daily intake of n-3 PUFAs.     

Influence of dietary fats upon systolic blood pressure in the rat

Studies were performed to determine whether feeding diets with differing fatty acid content and composition had an influence on systolic blood pressure in the rat. Weanling male rats were fed standard laboratory chow (2.9% fat in total), or synthetic diets (10% fat in total) containing fish oil, butter, coconut oil or corn oil, for 5 weeks. Coconut oil and butter diets were rich in saturated fatty acids, whilst fish oil and corn oil were rich in the n-3 and n-6 unsaturated fatty acids respectively. Systolic blood pressure was measured using an indirect tail-cuff method at the end of the feeding period, and compared to a group of weanling rats. Feeding the different diets did not alter the growth of the rats, so all animals were of similar weights at the time of blood pressure determination. Control (chow fed) animals, at nine weeks of age, had higher systolic blood pressures than the weanling, baseline control group. Fish oil fed rats had similar pressures to the chow fed rats. Corn oil fed rats had significantly lower systolic pressures than the controls. The rats led the diets rich in saturated fatty acids (butter and coconut oil) had significantly higher blood pressures than all other groups. Systolic blood pressure was found to be significantly related to the dietary intakes of saturated and unsaturated fatty acids. The dietary intake of linoleic acid was significantly higher in corn oil fed rats than in other groups. Systolic blood pressure was inversely related to linoleic acid intake. Feeding a diet rich in saturated fatty acids significantly increases blood pressure in the rat. A high intake of n-6 fatty acids, and in particular linoleic acid, appears to have a hypotensive effect. Prenatal exposure of the rats to a maternal low protein diet, abolished the hypertensive effects of the coconut oil diet and the hypotensive effect of the corn oil diet upon young adult females. The intrauterine environment may, therefore, be an important determinant of the effects of these fatty acids on blood pressure in later life.     

Effect of feeding raw and treated common vetch seed (Vicia sativa) on the performance and egg quality parameters of laying hens

Two experiments were conducted to study the effect of feeding raw or treated common vetch seeds (V) on BW, feed intake (FI), egg production (EP), feed conversion (FC), egg weight (EW), shell thickness (ST), yolk color score (YC), and Haugh unit score (HU) of Single Comb White Leghorn hens for 56 d. In Experiment 1, diets contained 0, 7.5, 15, and 22.5% raw V. Compared with the control, the 22.5% V diet decreased (P < .05) BW, FI, and EP. In Experiment 2, intact or ground (G) V were either soaked (S) in water (1:5) for 24 h or autoclaved (A) at 103.5 x 10(3) Pa for 8 h, and then dried (D) at 55 C for 24 h. Eight diets were used, a corn soybean (control) and seven others, each containing 25% V, previously subjected to the forementioned treatments as follows: untreated V (UV), SDV, GSDV, ADV, GADV, SADV, and GSADV. Compared with the control, the UV diet decreased (P < .05) FI (75 vs 98 g) and EP (47.3 vs 88.7%), increased FC (1.99 vs 1.4 kg feed per dozen eggs), and induced BW loss (-63 vs 49 g). Soaking intact V improved (P < .05) FI (85 g) and EP (69%). Remaining treatments resulted in further improvement. Hens fed all V diets produced eggs with HU score 13 points better than that of the control (P < .05). In both experiments, EW, YC, and ST were not different among treatments. Results indicated that autoclaved V at 25% level was not detrimental to layers' performance.     

]The substitution of protein feed by lysine-supplemented protein-rich wheat during the raisung and laying periods in hens. 6. Report. The effect of graded lysine supplemented on the crude nutritional content of the carcas of laying hen

In the present work 8 hens taken from each of the 16 experimental groups (90 birds per group) were killed at the end of the trial period (52 weeks). The weight of the organs was determined and bones, the utilizable parts and the residual carcass were analyzed for their crude nutrient content. The experimental birds received rations containing a large proportion of high-protein wheat supplemented with varying levels of lysine. Variations in the lysine supply did not affect the mass of blood, feathers, bones, liver, stomach, heart and ovaries, including ovarian follicles. An analysis of the utilizable parts (flesh, stomach, heart, liver, follicles, fat) for crude nutrients showed that the heavier birds receiving adequate amounts of lysine contained less crude protein and more crude fat than the smaller birds. A positive correlation was found to exist between the crude ash content of these samples (expressed as %) and the levels of lysine supplied during the laying period. All the birds receiving the lysine-deficient ration during the time of rearing or during the laying period contained significantly less crude ash in their bones. Alongside with the crude ash content the phosphorus content of the bones decreased when the birds where fed the diet for laying hens.     

Dietary stearic acid reduces plasma and hepatic cholesterol concentrations without increasing bile acid excretion in cholesterol-fed hamsters

Although there is general agreement that saturated fatty acids elevate plasma cholesterol concentrations, the relative effects of individual fatty acids on cholesterol and bile acid metabolism are less clear. In this study, cholesterol and bile acid responses to diets enriched in different saturated fatty acids were investigated in hamsters. The six diets examined were as follows: 5% fat (g/100 g) enriched in palmitic acid (16:0) with no cholesterol, 5% fat 16:0-enriched, 0.05% cholesterol (wt/wt), and four diets containing 0.05% cholesterol and 15% fat with each diet enriched in lauric (12:0), myristic (14:0), palmitic (16:0), or stearic acid (18:0). Total plasma cholesterol concentration was significantly greater in hamsters fed the 14:0-enriched diet relative to those fed the 18:0-enriched diet (P < 0.05). Both plasma and liver cholesterol concentrations of hamsters fed 18:0 did not differ from those of the group fed no dietary cholesterol. In all instances, differences in total plasma cholesterol were accounted for within the HDL fraction; no significant treatment differences in VLDL or LDL cholesterol were found. Total daily fecal bile acid excretion was higher in hamsters fed the 15% fat 16:0 diet compared with those fed no dietary cholesterol (P < 0.05), but not significantly different from other treatment groups. There was greater deoxycholic acid excretion (P < 0.05) from hamsters fed the 14:0 and 16:0 diets compared with those fed the 18:0-enriched diet. Small intestinal + gallbladder bile acids, an index of pool size, did not differ significantly among the groups. The observed relative hypocholesterolemic effect of stearic acid was not mediated by increased bile acid excretion.     

Fatty liver-hemorrhagic syndrome observed in commercial layers fed diets containing chelated minerals

This study was originally conducted to determine the effect of various chloride levels and consumption of chelated versus non-chelated minerals on egg production and eggshell breaking strength. However, the focus of this report changed after fatty liver-hemorrhagic syndrome (FLHS) was observed in hens that consumed diets containing chelated minerals. No FLHS was observed in hens that consumed a diet that contained non-chelated minerals. Four hundred thirty-two 35-week-old commercial laying hens were housed in individual cages in groups of nine hens each. The treatments were factorially arranged (3 x 2) such that six experimental diets differing in chloride levels and in source of minerals were fed for six 28-day laying periods. A significantly higher mortality attributed to FLHS was observed in hens that consumed the diets having chelated minerals as compared with hens that consumed the diets with non-chelated minerals. No difference in mortality was observed among the hens fed the various chloride diets.     

Effect of feeding clinoptilolite (zeolite) on the performance of three strains of laying hens

1. One hundred and twenty 16-week-old single combed pullets of three strains were fed on a diet containing 135 g protein/kg with or without 50 g clinoptilolite/kg in a trial with 20 hens per treatment. Sterile river sand replaced clinoptilotile in the control diet in order to keep the diets isoenergetic. The hens were individually caged in a naturally ventilated laying house and fed one of the two diets for ten 28-d periods. 2. Significant dietary effects of feeding clinoptilolite were observed with number of eggs laid per hen, shell thickness, efficiency of food utilisation and droppings moisture content. No significant dietary effects between treatments were observed with body weight, age at first egg, egg weight. Haugh units, food intake/hen and rate of amino acid absorption of radioactive lysine and methionine into the bloodstream. Significant differences between strains were observed with regard to all parameters except food intake/hen. There were no significant strain X clinoptilolite interactions.     

Effect of high dietary copper on fatty acid composition of the chick

Three experiments were conducted to study the effect of varying levels of dietary copper on fatty acid composition of adipose and liver tissue of male broiler chicks. Chicks were fed the experimental diets to 4 weeks at which time leg adipose and liver samples were obtained for fatty acid determination. Adding 500 or more p.p.m. copper to either a practical or corn starch-soy basal diet caused significant changes in fatty acid composition but the differences were variable perhaps due to a depression of growth caused by these levels of copper. Fatty acid composition of the tissue was not greatly affected by adding 250 p.p.m. of copper to the practical diet which contained 1.5% poultry fat. When a corn starch-soy diet was fed with 0, 2, or 8% added corn oil, the ratio of 16:0 + 18:0 to 16:1 to 18:1 was not lowered in leg adipose lipids by copper supplementation (250 p.p.m.) with any level of added corn oil. With liver lipids copper appeared to reduced the ratios in birds fed the diets with 0 or 2% added corn, but the differences were not statistically significant. The results indicate that using copper levels in practical diets that do not depress growth rate will not have much effect on fatty acid composition of carcass lipids and probably not on physical characteristics of the fat.     

Dietary fat saturation and chain length modulate guinea pig hepatic cholesterol metabolism

The effects of dietary fat saturation and saturated fatty acid composition on plasma lipoprotein concentrations and hepatic cholesterol metabolism were investigated in guinea pigs. Animals were fed semipurified diets containing 15 g fat/100 g diet, as palm kernel, palm oil, beef tallow, lard, olive oil or corn oil. Plasma lipoprotein concentrations were significantly altered by the type of dietary fat. The LDL cholesterol concentration was highest in animals fed the diet with palm kernel and lowest in animals fed the diet with corn oil, whereas HDL cholesterol was lowest in beef tallow-fed guinea pigs (P < 0.01). Hepatic cholesteryl ester concentrations were 100% higher in animals fed diets containing polyunsaturated corn oil and monounsaturated olive oil compared with animals fed any of the saturated fat diets (P < 0.01). Hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity varied in the different dietary fat groups independent of hepatic cholesterol pools or plasma LDL concentrations. In contrast, hepatic acyl-CoA: cholesterol acyltransferase (ACAT) activity was significantly correlated with plasma LDL cholesterol across all dietary groups (r = 0.63, P < 0.001). These data demonstrate that regulation of hepatic HMG-CoA reductase activity is relatively independent of changes in plasma lipoprotein levels, whereas hepatic ACAT activity exhibits a positive correlation with plasma LDL cholesterol concentrations.     

Differential accumulation and release of long-chain n-3 fatty acids from liver, muscle, and adipose tissue triacylglycerols

Eicosapentaenoic acid (EPA, 20:5n-3) is less efficiently accumulated in tissue triacylglycerols (TAGs) during fish oil feeding than docosahexaneoic acid (DHA, 22:6n-3) or docosapentaenoic acid (DPA, 22:5n-3), and EPA is preferentially released from the TAG of isolated adipocytes in vitro and adipose tissue in vivo during fasting compared with DHA or DPA. It is not known if this preferential release occurs in vivo under nonfasting conditions or if it is limited to adipose tissue. Accordingly, we have carried out experiments to study the turnover of EPA, DHA, and DPA in the TAG of adipose tissue, liver, and skeletal muscle. Weanling rats were fed diets containing fish oil for 6 weeks and then switched to diets containing only corn oil as the dietary fat for 8 weeks. The fatty acid composition and mass in epididymal fat pads, omental fat, liver, and soleus muscle TAGs were determined weekly for the first 10 weeks and at weeks 12 and 14. Subsequent to the change to the corn oil diet, EPA (20:5n-3), DPA (22:5n-3), and DHA (22:6n-3), which had accumulated during fish oil feeding, were lost from the tissue TAG pools of each tissue examined. After 8 weeks on the corn oil diet, less than 10% of the accumulated EPA, DPA, and DHA remained in the liver and muscle. The loss of EPA, DPA, and DHA from epididymal fat pad was slower. In each tissue, EPA was lost more rapidly than DPA or DHA. This selective loss of EPA relative to DHA or DPA may explain the previously reported underrepresentation of EPA compared with DHA or DPA in tissue TAG.     

Alteration of milk fat by variation in the source and amount of starch in a total mixed diet fed to dairy cows

The effect on milk yield and composition of the supplementation of the diets of dairy cows with wheat or potato peelings was studied at three different starch intakes (< 5, 6, and > 7.5 kg/d) for dry matter intakes around 20 kg/d. Starch supply was varied using different dietary concentrations of corn silage. Trials were conducted using Latin square designs, and all cows were fed a total mixed diet composed of corn silage, grass silage, or both; soybean meal; a mixed meal with formaldehyde treatment; minerals; and one of the following energy concentrates: potato peelings or wheat. Dry matter and energy intakes varied significantly only at the low starch concentration; higher intakes were observed when the potato peelings were fed. Body weight, milk yield, true protein content, lactose content, and protein yield were not affected by treatment. Milk fat content was higher (+3.3 g/kg) when potato peelings were fed at the high starch concentration but was unaffected at the low and medium starch concentration. Slow degradation of starch from the potato peelings in the rumen could enhance a higher delivery of precursors of milk fat synthesis in the udder. The effect on fat yield differed among starch concentrations. Milk fat content appeared to decrease for cows fed diets containing quickly degradable starch at a starch intake > 7 kg/d.