H. Everts

Effects of dietary essential oil components on growth performance, digestive enzymes and lipid metabolism in female broiler chickens

1. The present experiment was conducted to describe the effects of thymol, cinnamaldehyde and a commercial preparation of essential oil components (CRINA® Poultry), in female broilers. Feed and water were provided for ad libitum consumption. 2. Feed intake, weight gain and feed:gain ratio were not different among the treatments. Water intake was significantly lowered by cinnamaldehyde. Relative liver weight (g/100 g of body weight) was highest in birds given thymol, but this was seen only at the age of 21 d and not at 40 d. Patterns of digestive enzymes in pancreatic tissue were similar for the 4 treatments. 3. Amylase activity in intestinal digesta was highest in chickens given CRINA® Poultry for 21 d, but the effect had disappeared after 40 d. Ileal digestibility coefficients for starch and protein were high and identical for all treatments. 4. Fatty acid composition of diet was reflected in that of adipose tissue. Plasma lipid concentrations were not changed by any dietary treatment. 5. Thus, the present results show no effect of essential oil constituents on growth performance in female broiler chickens, but it cannot be excluded that positive effects would have been observed under less hygienic environmental conditions or when using a less digestible diet.

Play is indispensable for an adequate development of coping with social challenges in the rat

In this study, young rats were deprived of early social interactions during weeks 4 and 5 of life. Different behavioral tests were conducted in adulthood to study the behavioral responses of rats lacking early social experiences. Juvenile deprivation resulted in decreased social activity and an altered sexual pattern, but did not affect locomotor activity or the performance in the elevated plus maze. Furthermore, behavioral and neuroendocrine responses of juvenile isolated rats were dramatically altered when they were confronted with territorial aggression. Juvenile deprived rats did not readily display a submissive posture in response to the resident and showed no immobility behavior after being returned to the residents territory, while their plasma corticosterone and adrenaline concentrations were significantly increased compared to nonisolated controls. In contrast, behavioral responses in the shock prod test were not affected by previous isolation. The results suggest that early social experiences are vital for interactions with conspecifics later in life, i.e., aggression, sexual, and social interactions.

Growth performance of weanling pigs fed spray-dried animal plasma: a review

Spray-dried animal plasma (SDAP), mostly of porcine origin, is frequently used as an ingredient of weanling piglets diets in order to improve feed intake and to reduce post-weaning diarrhoea. On the basis of 15 published studies it is concluded that dietary SDAP levels up to 6% increase both average daily gain (ADG) and feed intake (ADFI) in the first 2 weeks after weaning in a dose-dependent fashion. Up to 6% SDAP also reduces feed conversion ratio (FCR). The positive effect of SDAP on ADG and ADFI is much more pronounced in the first than the second week after weaning. There is no positive carry-over effect of SDAP feeding during the period of 2 weeks after weaning on growth performance thereafter. SDAP is an expensive protein source and an economic evaluation should be made before including SDAP in weanling piglets diets. Multiple regression analysis indicated that, apart from SDAP dose, baseline growth rate is an important determinant of the effect of SDAP on ADG, with high baseline growth rate being associated with small effects of SDAP. It should be stressed that SDAP is a non-sterilised product that might spread certain diseases after feeding it to pigs. Porcine plasma has more beneficial effects than bovine plasma. Possible modes of action are discussed. It is suggested that, in addition to improving feed palatability, SDAP reduces post-weaning intestinal disease by preventing attachment of pathogens.

Coping with stress in rats and mice: Differential peptidergic modulation of the amygdala-lateral septum complex

This chapter focuses on the parvicellular vasopressin (VP) system originating from the medial nucleus of the amygdala (MeA) and bed nucleus of the stria terminalis (BNST). The vasopressinergic fibers of these nuclei innervate a number of limbic brain areas including the septum-hippocampal complex. Interestingly, this VP system is sexually dimorphic and the VP synthesis in this system depends on circulating gonadal steroids. Studies in rats and mice show that the variation in the lateral septal VP network within the male gender is as large as the variation between the sexes as reported in the literature. Non-aggressive males are characterized by a far more extensive VP network and a higher VP content in the lateral septal area than aggressive males. A review of the literature on the function of lateral septal VP in the organization of behavior reveals not only a modulatory role of behavior in a social context, but also of fear- and anxiety-related behaviors. It is argued that these seemingly diverse functions might be explained by the concept of coping style. Extensive behavioral and physiological analyses in a variety of animal species show that males may be characterized by the way in which they cope with environmental challenges in general. Aggressive males tend to cope actively with their environment whereas non-aggressive males seem to accept the situation as it is more easily. In several tests, we determined the effects of chronic infusion of the V1 receptor antagonist locally into the lateral septal area in male rats. The main conclusion from these experiments is that LS VP does not modulate coping style in general. However, the experiments confirm the idea that LS VP has a certain degree of functional specificity in social behavior and social learning tasks. Together with the observation that the size and distribution of the vasopressinergic system may be highly variable between individual males in relation to their coping style, this suggests that the lateral septal vasopressinergic system is involved in the differential capacity of individuals to cope behaviorally with challenges of a social nature.

Differential lateral septal vasopressin in wild-type rats : Correlation with aggression

The vasopressin (VP)-containing projections from the cells of the bed nucleus of the stria terminalis to the lateral septum (LS) are sexually dimorphic and dependent on gonadal steroids. Recently, the difference in VP distribution found among both sexes was also demonstrated in male mice genetically selected for different levels of intermale aggression. In the present study we examined whether this differential VP distribution in males also exists in an outbred strain of wild-type rats. After the animals were tested for their level of aggression, the VP content and the fiber density of the LS were measured using radioimmunoassay and immunocytochemistry, respectively. In addition, basal levels of plasma testosterone (T) were measured. Both biochemical data and immunocytochemical data revealed a negative correlation between VP and intermale aggression. Aggressive rats exhibited low levels of VP whereas intermediate and nonaggressive animals showed higher levels. Differences in adult levels of T were not found. The results are in accordance with the observations previously found in male mice, reconfirming the correlation between lateral septal VP and aggression.

Retrospective study of the survival of cats with acquired chronic renal insufficiency offered different commercial diets

A retrospective study was carried out on the efficacy of seven commercial diets designed to be fed to cats with chronic renal failure. The median survival time of 175 cats that received conventional diets was seven months, whereas the median survival time of 146 cats given one of the seven diets was 16 months. The cats on the most effective of the diets had a median survival time of 23 months and those on the least effective diet had a median survival time of 12 months. The composition of the seven diets was comparable, except that the most effective diet had a particularly high content of eicosapentaenoic acid.

Effect of dietary fat type on meat quality and fatty acid composition of various tissues in growing-finishing swine

Thirty-six castrated male growing pigs were used to study the effect of dietary beef tallow (BT) versus sunflower oil (SO) on meat quality and fatty acid composition of various tissues. The diets used contained either 5% (w/w) of the variable fat source. The fat type had no significant effect on carcass traits (carcass weight, back-fat thickness, fat-lean ratio) and meat quality (colour, pH(1), pH(U), drip losses, cooking losses, shear force, sacromere length, loin moisture, loin marbling). The diet with SO instead of BT significantly increased the incorporation of polyunsaturated fatty acids in adipose tissues, loin and liver at the expense of the sum of saturated and monounsaturated fatty acids. In erythrocytes, the diet containing SO raised the contents of saturated and polyunsaturated fatty acids and lowered that of monounsaturated fatty acids. In particular, the SO diet produced an increase in the content of linoleic acid (C18:2n-6) in the various tissues. It is concluded that feeding a diet with SO instead of BT altered the fatty acid composition of tissues without simultaneously affecting various characteristics of meat quality.

Mathematical relationships between the intake of n-6 and n-3 polyunsaturated fatty acids and their contents in adipose tissue of growing pigs.

To establish the relationships between the fatty acid composition of adipose tissue in growing pigs and the intake of fatty acids, we performed a feeding trial and did a literature survey. Six groups of pigs were fed diets with variable combinations of corn, linseed and fish oil. After 38 days, biopsies of adipose tissue were analyzed for their contents of linoleic, α-linolenic, eicosapentaenoic and docosahexaenoic acid. For the four fatty acids, intake data and adipose tissue levels were also collected from the literature. Linear correlations were computed for the intake of each polyunsaturated fatty acid and its level in adipose tissue, the data set consisting of either the original results only or combined with literature figures. The observed strong correlations between dietary and fat tissue polyunsaturated fatty acids indicate that the fatty acid composition of the diet may be used as an index of the fatty acid composition of the diet, and vice versa. The regression equations presented can be used to steer the fatty acid composition of adipose tissue of growing pigs by the fatty acid composition of their diet.

The effect of six different C18 fatty acids on body fat and energy metabolism in mice

We studied the effects of five high-fat semi-purified diets varying at a 4% (w/w) level in either stearic, oleic, linoleic, alpha-linolenic, or gamma-linolenic acid on body fat and energy metabolism in BALB/c mice. A diet containing caprylic, capric, lauric, and myristic acid was used as a reference diet and a diet with 4% conjugated linoleic acid (CLA) was used as a positive control as it is known to effectively lower body fat in mice. The diets were fed for 35 d. Body fat was significantly lower in the CLA group than in the other groups but was not significantly different among the non-CLA groups. Among the non-CLA groups, the linoleic acid group tended to have the highest and the alpha-linolenic acid group the lowest proportion of body fat. In energy-balance studies, the percentage of energy intake that was stored in the body was significantly lower in the CLA group compared with the other dietary groups. The percentage of energy intake eliminated in excreta was highest in the stearic acid group followed by the gamma-linolenic acid group. These results were reflected in apparent fat digestibility, which was lowest in the stearic acid group. The percentage of energy intake expended as heat was highest in the CLA-fed mice. The results of the present study suggest that body fat and energy accretion in mice fed diets containing different C18 fatty acids is by far the lowest with CLA and that linoleic acid produced the highest fat intake and energy accretion.

Effect of dietary conjugated linoleic acid on body composition and energy balance in broiler chickens

The effect of dietary conjugated linoleic acid (CLA) on body composition and energy metabolism was investigated in broiler chickens. Male broiler chicks were assigned to receive either a control diet (1 % sunflower oil) or a diet containing CLA (1 % of a 1:1 mixture of trans-10, cis-12 and cis-9, trans-11 isomers of octadecadienoic acid). The diets were fed ad libitum for 3 weeks and there were eight replicates per diet, each replicate including four chickens so that each treatment had thirty-two animals. The proportion of body fat was lower in the control group than in the CLA group. No significant differences as to the proportions of body water, ash and protein were observed. Feed and energy intake were significantly lower in CLA-fed birds. The percentage of ingested energy lost in excreta was higher after CLA feeding and heat expenditure as a percentage of ingested energy was lower in the CLA-fed group. The CLA-fed group showed a higher percentage of SFA and lower percentages of MUFA and PUFA in carcass fat. It is concluded that CLA stimulated de novo fatty acid synthesis and lowered desaturase activity.