Metabolic Effects of a Hydrophobic Alginate Derivative and Tetrahydrolipstatin in Rats Fed a Diet Supplemented with Palm Fat and Cholesterol.

The effects of octadecylamide of alginic acid (amidated alginate) and tetrahydrolipstatin on serum and hepatic cholesterol, and the faecal output of fat and sterols, were investigated in rats. Amidated alginate is a sorbent of lipids, tetrahydrolipstatin is an inhibitor of pancreatic lipase. Rats were fed diets containing cholesterol and palm fat at 10 and 70 g/kg, respectively. Palm fat was provided by coconut meal. Amidated alginate at 40 g/kg diet significantly decreased serum total cholesterol, low-density lipoprotein and hepatic cholesterol, and hepatic lipids and increased the faecal output of fat and coprostanol. Tetrahydrolipstatin at 300 mg/kg diet significantly decreased low-density lipoprotein cholesterol and hepatic lipids and increased the faecal output of fat. The intake of feed was not significantly influenced; however, the weight gains in rats fed amidated alginate were lower than in rats of the control group. Both amidated alginate and tetrahydrolipstatin modified the fatty acid profile in excreta lipids. Concentrations of saturated fatty acids were decreased and those of unsaturated fatty acids increased. Despite different modes of action, amidated alginate and tetrahydrolipstatin were equally efficient in removing the dietary fat from the body.

Economic values of rabbit traits in different production systems.

In animal breeding, genetic parameters along with economic weights (EWs) of traits are applied. Profit functions currently used to calculate rabbit traits' EWs do not consider nutrient requirements based on animal weight, growth rate and doe reproductive status. Therefore, the aim of this study was to develop a flexible bioeconomic model of rabbit-production systems and implement it in a computer programme in order to calculate economic values and relative EWs for rabbit traits. The bioeconomic model includes calculation of the doe age structure in the stationary state of a doe population; calculation of progeny structure; modelling growth, digestible energy, feed and water requirements for does in different reproductive statuses and for all progeny groups using a normative approach; calculation of the total feed and non-feed costs, revenues and profit per doe and per year; calculation of marginal economic values for up to 20 production and functional traits and estimation of the relative EWs of selected traits. The application of the programme is shown through an example calculation of trait economic values for a typical Czech commercial rabbit-production system. The trait economic value expresses the change in profit per doe and per year when the trait mean is increased by one unit. The programme developed is primarily useful for selection purposes in rabbit-breeding systems. Using this programme, some economic analyses of the impact of production, management and economic circumstances on the economic efficiency of various rabbit-production systems can also be performed.

Narrow-leaved lupine seeds as a dietary protein source for fattening rabbits: a comparison with white lupine seeds.

Lupine seeds have the potential to be an alternative to imported dietary proteins. In rabbits, it has been indicated that White lupine seed (WLS) is a suitable protein source. Other lupine species, for example, narrow-leaved lupine seed (NLS), have not yet been tested in rabbit diets. Two experiments were carried out to evaluate the effect of the dietary inclusion of NLS on growth performance, sanitary risk index (SRI), coefficients of total tract apparent digestibility (CTTAD) and nitrogen output in fattening rabbits. Narrow-leaved lupine was compared with WLS as a main protein source. For Experiment I, a total of 198 Hyplus rabbits (37 days of age) were allocated into two groups (99 rabbits per group), fed the WLS I diet (120 g/kg of WLS cv. Amiga) or the NLS I diet (150 g/kg of NLS cv. Probor), and used for performance and carcass trait evaluations. In addition, the CTTAD of the diets and the nitrogen output were determined in 10 Hyplus rabbits per treatment (37 days of age). For Experiment II, a total of 180 Hyplus rabbits (32 days of age) were allocated into two groups (90 rabbits per group), fed the WLS II diet (120 g/kg of WLS cv. Amiga) or the NLS II diet (130 g/kg of NLS cv. Primadona), and used for performance and carcass trait evaluations. In addition, the CTTAD of the diets was determined in 10 Hyplus rabbits per treatment (32 days of age). Regardless of the treatment, the dietary inclusion of NLS had a negative effect on growth of the rabbits. The nitrogen excretion and coefficients of nitrogen retention of rabbits were not affected by the treatments. In Experiment I, SRI (37 to 80 days of age) was higher in rabbits fed the NLS I diet than in those fed the WLS I diet (38.4% v. 23.2%, respectively; P = 0.031). Similarly, in Experiment II (32 to 74 days of age), SRI was higher in rabbits fed the NLS II diet than in rabbits fed the WLS II diet (37.8% v. 23.3%, respectively; P = 0.052). In conclusion, regardless of the variety, the dietary inclusion of NLS had no negative effect on the nitrogen output or dressing-out percentage of rabbits when compared to those of rabbits fed the WLS diets. With respect to the SRI and performance, however, NLS did not provide a satisfactory outcome.

The relationship between hepatocytes and small bowel after early and short food restriction: What the results show in morphometry.

The objective of this study was to evaluate the relationship between hepatocyte morphometry and small bowel architecture after early and short food restriction. Altogether 48 Hyplus broiler rabbits were divided into three groups. The control group was fed ad libitum (ADL) throughout the experiment (C). The first group were food-restricted between 32 and 39 days of age, when the rabbits received 50g of food per rabbit each day (R1). The second group was restricted between 32 and 39 days and the rabbits received 65g of food per rabbit each day (R2). In 39 and in 81 days eight rabbits from all three groups were euthanized. The diameter of centrilobular, midzonal and periportal hepatocytes and the height of villi, the width of villi and the crypt depth were measured. The hepatocytes grew from centrilobular to perilobular part in the C group, but in the R1 and R2 group, an opposite trend was noticed. On day 39 and daye 81 the elevations of villi were the highest. Interestingly, the nadirs of the crypts were deepest in the C group compared to the R1 and R2 groups. Early short intensive food restriction may play a role in the prevention of liver diseases (Tab. 2, Ref. 20).

The influence of food restriction on the small bowel: Does intensive short­term food restriction lead to weight loss?

The objective of this study was to show morphological changes in the small intestine of Hyplus broiler rabbits following an eight­day food restriction programme. The control group (C) received food ad libitum (ADL) for the duration of the experiment. Group R1 received 50g of food per day, and group R2 received 65g of food per day. After the food restriction diet had been completed, groups R1 and R2 were returned to ad libitum feeding. After food restriction and at the end of the experiment, the longest small bowel measurement was recorded in the C group. In the C group, after food restriction, the villi height was significantly higher, compared to that in R1 and R2 groups and at the end of the experiment, the villi were significantly higher in R1 and R2 groups. After food restriction, the values of crypts depth were approximately similar in all groups, and the end of experiment, the depth of crypts were deepest in R1and R2 groups, as compared to that in C group. The full process is followed by weight loss to the end of the experiment. These data suggest that intensive short­term food restriction followed by ADL feeding has effect on weight loss (Fig. 3, Ref. 30).

The effect of 1-week feed restriction on performance, digestibility of nutrients and digestive system development in the growing rabbit.

A 3 to 4 week feed restriction of about 20% to 25% of the free intake is widely applied in rabbit breeding systems to reduce post-weaning digestive disorders. However, a short intensive feed restriction is described in few studies and can be beneficial for growing rabbits due to a longer re-alimentation period. The aim of this study was to evaluate the effect of ad libitum (AL) and two restriction levels of feeding (50 and 65 g/rabbit per day) applied for 1 week on performance, gastrointestinal morphology and physiological parameters during the restriction and during the re-alimentation period. Rabbits were divided into three experimental groups: AL rabbits were fed AL, R1 rabbits were restricted from 42 to 49 days of age and received 50 g daily (29% of AL) and R2 rabbits were restricted at the same age and were fed 65 g of feed daily (37% of AL). In the 1(st) week after weaning and in the weeks after restriction, all the groups were fed AL. During the restriction period, daily weight gain (DWG) in R1 significantly dropped to 11% (experiment 1) and 5% (experiment 2) compared with rabbits in the AL group, although they were fed 29% of AL, whereas in the R2 group it decreased to 20% (experiment 1) and 10% (experiment 2). In the week following feed restriction, DWG in the restricted groups increased (P<0.001) to 166% and 148% in R1 and to 128% and 145% in R2. Restricted rabbits in both the experiments reached up to 90% to 93% of the final live weight (70 days) of the AL group. Over the entire experimental period, feed restriction significantly decreased feed intake to 85% to 88% of the AL group; however, the feed conversion ratio was lower (P<0.05) only in experiment 1 (-6% in R1 and -4% in R2). Digestibilities of CP and fat were not significantly higher during the restriction period and during the 1(st) week of re-alimentation compared with the AL group. Significant interactions between feeding regime and age revealed the shortest large intestine in the AL group at 49 days of age and the longest at 70 days in the AL and R1 groups. Small intestinal villi were significantly higher and the crypts were significantly deeper in the restricted groups. It could be concluded that short intensive feed restriction increased digestible area in the small and large intestines, including the height of villi and depth of crypts, which might be involved in the compensatory growth and defence mechanism.

Effect of diets containing whole white lupin seeds on rabbit doe milk yield and milk fatty acid composition as well as the growth and health of their litters.

The effect of dietary inclusion of white lupin seed (WLS) on the milk composition and yield of rabbit does as well as the performance of their litters was studied. Two lactation diets having identical digestible protein (DP):DE ratio and two weaning diets having identical DP:DE ratio were formulated. The first lactation diet (SL) contained soybean meal (SBM; 13.0%) and sunflower meal (5.0%) as the main CP sources, whereas the second lactation diet (LL) was based on WLS (25.0%). As a result, the LL diet had a greater ether extract (EE) content than did the SL diet. The first weaning diet (SW) included SBM (7.0%) as the main CP source, whereas the second weaning diet (LW) diet was based on WLS (12.0%). No additional fat was added to any of the diets. A total of 32 (16 per treatment) Hyplus PS 19 does (4,225 ± 607 g BW, at the second parturition) were fed 1 of the 2 lactation diets. The litters were standardized to 9 kits (564 ± 81 g BW) on the day of birth and were fed 1 of the 2 weaning diets from d 17 to 69 of age. At d 30 of age (weaning), 66 rabbits on each weaning diet (689 ± 71 g BW; 3 per cage) were used to evaluate performance. Feed intake and doe BW were not affected by the dietary treatments. Milk yield tended to be higher between d 1 and 30 of lactation in does fed the LL diet (P = 0.094), a finding that is related to the higher dietary EE content and intake in the LL diet. When expressed per kilogram of metabolic weight, milk output (P < 0.05) and fat output (P < 0.05) were greater in these does. Improved G:F (P < 0.05) between d 1 and 21 of lactation and greater ADG (P = 0.072) and milk efficiency (P < 0.05) of litters was observed in does fed the LL diet. The milk of does fed the LL diet contained less linoleic acid (P < 0.05) and arachidonic acid (C 20:4n-6; P < 0.05) and more oleic acid (P < 0.05), α-linolenic acid (P < 0.05), and eicosapentaenic acid (P < 0.05), with a corresponding increase in the total PUFA n-3:C 20:4n-6 ratio (P < 0.05). The performance of fattening rabbits was not affected by dietary treatment. The number of ill plus dead rabbits caused by digestive disease was lower (P < 0.05) in rabbits fed the LW diet. Therefore, WLS is a suitable dietary CP source for lactating does that can replace traditionally used CP sources without adverse effects on feed intake and milk yield or on the growth and viability of their litters. Due to its fatty acid (FA) composition, the use of WLS in the lactation diet has the potential to improve the milk FA composition of does.

Effect of a starter diet supplementation with mannan-oligosaccharide or inulin on health status, caecal metabolism, digestibility of nutrients and growth of early weaned rabbits.

The effect of a dietary supplementation with mannan-oligosaccharide (MOS, Bio-Mos, Alltech Inc.) and inulin (Frutafit® IQ) on growth, health, and caecal traits was studied on 348 rabbits (Hyplus®), weaned at 25 days of age. Three hundred and thirty rabbits (110 per group) were used for the health status and growth performance trial, while 18 rabbits (six per group) were used for caecal metabolism evaluation at the age of 42 days of age. Three diets were formulated: C (control), M (0.3% MOS) and I diet (4% inulin). Digestibility of the diets was measured in 10 rabbits per group between 36 and 40 days of age. The control diet was fed to rabbits of the C group from weaning to 74 days of age (slaughter). Diets M and I were fed to rabbits of the respective group from weaning to 46 days of age, then were fed with control diet till slaughter. From 25 to 46 days of age, the weight gain was slightly higher in control rabbits ( P = 0.11), while no differences were recorded for the whole period. No differences among groups in the mortality, which was high due to an enteropathy-infected environment, were significant. The lowest morbidity ( P = 0.05) as well as the health risk index were recorded in rabbits fed the diet with inulin ( P = 0.03). After change of diet, the health risk index increased in the rabbits previously fed the diet with additives, thereby no significant differences in the health status were recorded for the whole period. Total caecal volatile fatty acids concentration was higher ( P < 0.01) and the pH ( P < 0.01) and ammonia concentration ( P = 0.01) lower in rabbits fed the inulin diet than in other rabbits. In these animals, acetate molar proportion was higher ( P = 0.01) and that of propionate as well as the propionate/butyrate ratio significantly lower than in other rabbits. Butyrate molar proportion was higher in rabbits fed the diet with MOS ( P < 0.01). In rabbits fed the inulin diet a higher activity of inulinase was recorded ( P < 0.001) than in other rabbits. A significantly lower digestibility of cellulose was observed in rabbits fed the diet with MOS. The results of our study suggest the importance of using inulin-type fructans in the nutrition of young rabbits. The higher health risk index of rabbits after change of diets indicates that prebiotics should be given for a longer time during the fattening period.

Effect of pectin and amidated pectin on cholesterol homeostasis and cecal metabolism in rats fed a high-cholesterol diet.

Two experiments were performed to compare the effect of pectin and its hydrophobic derivatives on homeostasis of cholesterol and cecal metabolism in male young rats. Control rats were fed a diet supplemented with palm fat and cholesterol (50 and 10 g/kg, respectively). Rats of other groups were fed the same diet containing citrus pectin or octadecylpectinamide (60 g/kg). Diets were fed for 4 weeks. In experiment I, pectinamide of lower degree of amidation (30 %) increased serum HDL cholesterol from 1.20 to 1.43 micromol/ml (p>0.05) at the expense of other cholesterol fractions. In experiment II, pectinamide of a higher degree of amidation (53 %) significantly decreased total serum cholesterol from 2.08 to 1.67 micromol/ml. Amidated pectins at both levels of substitution significantly decreased hepatic concentrations of cholesterol and fat. In both experiments the relative weight of cecum in the pectinamide group was significantly lower than in pectin group. The highest cecal concentrations of short-chain fatty acids (SCFA) were found in rats fed a diet with pectin (133.2 and 129.3 micromol/g in experiment I and II, respectively). In other groups, cecal SCFA was significantly (pectinamide groups) or non-significantly (controls) lower. In wet feces, SCFA concentrations were higher and butyrate molar proportions lower than in corresponding cecal contents. Pectinamide of a lower or higher degree of substitution significantly increased fecal content of cholesterol from 18.5 and 17.3 micromol/g in controls to 31.8 and 28.0 micromol/g, respectively. Corresponding concentrations of coprostanol were decreased. Effects of pectin on cholesterol homeostasis were absent or marginal. Histological examination revealed that hepatic tissue of control and pectin-fed rats was infiltrated with lipids. The Sudan black-positive material was absent in the liver of rats fed pectinamides. No pathological changes of liver tissue were apparent. In summary, hydrophobic amidated pectins significantly altered cholesterol homeostasis in rats and might be considered as a clinically effective hypocholesterolemic agent. Low cecal SCFA concentrations in rats fed pectinamides suggest that amidation of pectin had decreased its fermentability.