Effect of cholesterol feeding on serum lipoproteins and atherosclerosis in atherosclerosis-susceptible and atherosclerosis-resistant Japanese quail

Dietary processed former foodstuffs for broilers: impacts on growth performance, digestibility, hematobiochemical profiles and liver gene abundance

BACKGROUND

The present experiment aimed to evaluate the effects of commercially processed former foodstuffs (cFF) as dietary substitutes of corn, soybean meal and soybean oil on the growth performance, apparent total tract digestibility (ATTD), hematobiochemical profiles, and liver gene abundance in broiler chickens. Two hundred one-day-old male ROSS-308 chicks were assigned to 4 dietary groups (5 replicates of ten birds per replicate) according to their average body weight (BW, 38.0 ± 0.11 g). All groups received a two-phase feeding program: starter, d 1-12 and grower, d 12-33. The control group (cFF0) was fed a standard commercial feed based on corn, soybean meal and soybean oil. The other three groups received diets in which the feed based on corn, soybean meal, and soybean oil was partially replaced with cFF at a substitution level of 6.25% (cFF6.25), 12.5% (cFF12.5) or 25% (cFF25) for the following 33 d.

RESULTS

The growth performance data showed no differences in BW or average daily gain among groups, although the average daily feed intake decreased during the grower period (12-33 d) and over entire experimental period (1-33 d) in a linear manner as the cFF inclusion level rose (P = 0.026), positively affecting the gain to feed ratio (P = 0.001). The ATTD of dry matter of the cFF-fed groups were greater with respect to control group and increased throughout the experimental period, whereas the ATTD of ether extract linearly decreased with increasing levels of cFF-fed groups compared with control group and throughout the experimental period (P < 0.05). Additionally, a linear increase in the heterophil to lymphocyte ratio, serum cholesterol, triglycerides and alanine-aminotransferase were observed with increasing dietary levels of cFF (P < 0.05); however, no differences were observed in lipoprotein lipase or sterol regulatory element binding transcription factor gene abundance.

CONCLUSIONS

The results of this experiment demonstrate that it is possible to incorporate cFF into nutritionally balanced diets for broiler chickens, even up to 25% substitution levels, for up to 33 d without adversely impacting the overall growth performance of male broiler chickens raised under commercial conditions. Further studies are essential to validate the hematological trait findings.

Total cholesterol, total triglycerides, and cholesterol distribution among lipoproteins as predictors of atherosclerosis in selected lines of Japanese quail

The proportions of plasma high and low density lipoprotein cholesterol have been linked to inherited tendency for atherosclerosis in humans. Studies were conducted with Japanese quail males from lines genetically selected for high and low TC and a randombred (unselected) control line that were fed 0.0 or 0.5% cholesterol for 12 weeks. Atherosclerotic plaques were more severe in the high than in the low line quail and in those fed cholesterol compared to non-cholesterol-fed quail. Serum TG, TC, VLDLC, LDLC, and HDLC were also higher in the high than in the low line quail and in cholesterol-fed vs. non-cholesterol-fed quail. Significant interactions indicated that TC and LDLC concentrations were more affected by dietary cholesterol in the high line than in the low line. The low line quail maintained higher HDLC and lower LDLC than the high line. Regression and correlation analyses revealed that although VLDLC, LDLC, and TC were significant predictors of atherosclerosis in the high line birds, the TC/HDLC ratio was a better predictor in the low line. The Japanese quail lines used herein represent useful experimental models for studies of genetic differences in atherosclerosis in humans.

Lipoprotein and apoprotein profile of Japanese quail

The present study delineated the lipoprotein and apoprotein distribution in Japanese quail. Quail lipoprotein was composed of three fractions: VLDL, d < 1.020; LDL, 1.020 < d < 1.081; HDL, 1.081 < d < 1.210. When animals were fed the cholesterol-free diet, HDL was the predominant form, LDL intermediate, VLDL and chylomicron were smallest in amount. Feeding of cholesterol induced a marked change in the lipoprotein profile: VLDL or chylomicron predominated over HDL and LDL. An apoprotein of 26 kD (molecular weight) was the major protein moiety comprising more than 50% of total apoprotein in the entire density range of lipoprotein class. Amino acid composition of 26 kD protein was similar to hen, rat and human apo A-I. N-Terminal 36 amino acid sequence of 26 kD protein showed 92% homology to chicken apo A-I and 11% homology to human apo A-1. The 26 kD protein did not react with the antibody raised against human apo A-I. These observation showed that the 26 kD protein was partially identical to apo A-I.

Body, abdominal fat, and testes weights, and line by sex interactions in Japanese quail divergently selected for plasma cholesterol response to adrenocorticotropin

Line by sex interactions of BW, abdominal fat, testes weight, and plasma cholesterol were investigated in two Japanese quail lines. High (H-PCHOL) and low (L-PCHOL) quail lines had been developed by 18 generations of divergent selection for plasma cholesterol response to adrenocorticotropin (ACTH). Quail were from Generation 28 breeders maintained under a normal environment with no exposure to exogenous ACTH after Generation 18. Quail from growth-selected lines were also used to examine relationships between BW and plasma cholesterol. Body weights of H-PCHOL quail were significantly (P less than or equal to .05) heavier than BW of L-PCHOL quail at 2 and 4 wk of age. However, at 8, 16, and 28 wk BW were similar. Quail from long-term, growth-selected lines were observed to have plasma cholesterol levels similar to those of control lines. Therefore, early BW changes in H-PCHOL and L-PCHOL lines may not be related to plasma cholesterol changes. At 2 and 4 wk, male and female plasma cholesterol values were similar in the H-PCHOL and L-PCHOL lines, however, at 8 and 16 wk males had higher values than females in the H-PCHOL line, and females had higher values than males in the L-PCHOL line. Because interactions were present only after sexual maturity was reached, sex hormones may be involved in the expression of these interactions. Quail in the L-PCHOL line were observed to have significantly (P less than or equal to .05) more abdominal fat and significantly (P less than or equal to .05) smaller testes than quail in the H-PCHOL line.

Plasma and yolk cholesterol levels in Japanese quail divergently selected for plasma cholesterol response to adrenocorticotropin

Studies were conducted to determine the effect of divergent selection for plasma cholesterol response to adrenocorticotropin (ACTH) on the levels and relationships between plasma and yolk cholesterol in Japanese quail. Cholesterol data were obtained in Generation 25, following seven generations of relaxed selection, from birds maintained under a normal environment with no exposure to exogenous ACTH. Levels of plasma and yolk cholesterol were determined at 22 and 28 wk. Plasma cholesterol levels of quail in the low cholesterol line were significantly (P less than .01) lower than levels in the high line at both ages (224 versus 383 and 209 versus 326 mg/100 mL, respectively). In contrast, yolk cholesterol levels were significantly (P less than .01) higher in the low line than in the high line (24.1 versus 21.5 and 21.1 versus 16.9 mg cholesterol/g yolk at 22 and 28 wk, respectively). A significant line by sex interaction was present at both ages for plasma cholesterol with females having higher cholesterol values than males in the low line and males having higher values than females in the high line. A negative relationship was observed between changes in plasma and yolk cholesterol in the selected lines. Greater deposition of cholesterol in the yolk of the line with lower plasma cholesterol indicates that excretion rate may play a role in explaining genetic differences in plasma cholesterol.