Influence of age at weaning and nutritive value of weaning diet on growth performance and caecal traits in rabbits

[EN] To investigate the relationship between dietary nutrient concentration and weaning age on growth performance and caecal characteristics of rabbits, a trial was carried out on 64 litters (eight rabbits/litter) comparing two weaning ages (25 vs. 34 d) and two diets (HC: high concentrated and LC: low concentrated diet) offered to the kits from 18 to 34 d of age. At 34 d of age 54 animals per group were caged individually and all were fed the LC diet until 45 d of age. All animals were then fed a standard fattening diet (37% neutral detergent fiber, 3.4% ether extract and 18.0% crude protein on dry matter basis) until slaughter at 80 d. The digestibility trial was performed from 56 to 60 d of age on another group of 16 rabbits (8 per diet). During the experimental period (18-80 d of age), feed intake and animal weights were recorded. Caecal volatile fatty acids were measured at 45 and 80 d of age, while microbiological analysis was performed at 25 and 34 d on healthy suckling rabbits. Digestibility of dry matter, protein, neutral detergent fiber, fat and energy was higher in rabbits fed the HC diet (by 7.7, 7.4, 13.1, 26.7, 10.6%, respectively; P<0.001) than in those fed the LC diet. Growth rate and feed conversion ratio (FCR) from 18 to 34 d improved by 7.7 and 9.5% in rabbits fed HC in comparison to the LC diet, respectively (P¿0.061). Diet offered around weaning did not influence growth rate or FCR from 34 to 80 d of age. Rabbits weaned earlier increased feed intake (by 67.8%) from 25 to 34 d, but reduced growth rate (by 26.8%) compared to animals weaned at 34 d (P<0.001). Early weaning reduced live weight during the entire fattening period (P¿0.018), as well as the FCR (by 4%; P<0.001). Caecal pH was lower at 45 d of age in rabbits weaned at 25 d than in those weaned at 34 d (5.53 vs. 5.83; P=0.019). Treatments did not affect total caecal VFA concentration, but HC diet decreased caecal acetic concentration and increased butyric acid level compared to the LC diet at 45 d (P¿0.001). HC diet tended to reduce caecal counts of Enterobacteriacae (P=0.093), while it did not affect facultative anaerobic bacteria, E. Coli and Costridium spp. The LC diet increased at 25 d the number of Clostridium perfringens in comparison with the HC group at the same age and in comparison with animals fed both two diets at 34 d (P<0.001). The values of E. Coli and Enterobacteriaceae increased (P¿0.008) from 25 to 34 d of age, whereas that of Clostridium spp. decreased. Weaning at 25 d increased mortality from 18 to 34 d compared with rabbits weaned at 34 d (7.02 vs. 2.46%, P=0.017). However, during the fattening period (34-80 d) rabbits weaned earlier showed lower mortality (7.41 vs. 17.6%; P=0.024).This work has been realized within the CUNISVEZZ research project financed by the Agricultural Department of the Regione Lombardia as part of the 2004 research and development plan, d.g.r. 30/04/2004 n. VII/17326. The authors wish to thank Nicoletta Cesari for her technical assistance.Cesari, V.; Grilli, G.; Ferrazzi, V.; Toschi, I. (2009). Influence of age at weaning and nutritive value of weaning diet on growth performance and caecal traits in rabbits. World Rabbit Science. 17(4):195-205. https://doi.org/10.4995/wrs.2009.64419520517

Effect of weaning age and diet on growth performance, caecal characteristics and potential pathogenetic microflora in rabbits

The aim of this study was to investigate the effect of age and diet at weaning on growth performances, caecal characteristics and development of potential pathogenetic microflora. The trial was carried out on 64 litters from 18 to 45 days of age comparing two weaning age (25 vs. 34 d) and two weaning diets (HF and LF) characterized, especially, by different energy, fat and starch concentration (HF: DE=11.5 MJ/kg, EE=6.2%, Starch=8.7%; LF: DE=10.1 MJ/kg DM, EE=3.1%, Starch=11.3%). At 45 d, early weaning determined a significant reduction of growth (1219 vs. 1282; P<0.01), although the solid feed intake resulted significantly higher, from 25 to 34 days of age, in early weaned rabbits (50.0 vs. 29.8 g/d; P<0.001). The age at weaning did not modify caecal traits, with the exception of pH value, that was lower in rabbits early moved to the mothers (5.53 vs. 5.83; P<0,05). Independently by age of weaning, the administration of diet HF promoted growth performance in rabbits at 45 d (1280 vs. 1222; P<0.01). Diet composition did not influence mortality rate at 34 days of age, while early weaning determined values significantly higher than those found in rabbits weaned later. The data of microbial analysis, carried out on 10 animals per diet (at 25 and 34 days of age), showed potential pathogenetic microflora development depended by the age of animal and was not affected by the composition of diets

Premartensitic transition driven by magnetoelastic interaction in bcc ferromagnetic Ni2MnGaNi_{2}MnGa

We show that the magnetoelastic coupling between the magnetization and the amplitude of a short wavelength phonon enables the existence of a first order premartensitic transition from a bcc to a micromodulated phase in $Ni_{2}MnGa$. Such a magnetoelastic coupling has been experimentally evidenced by AC susceptibility and ultrasonic measurements under applied magnetic field. A latent heat around 9 J/mol has been measured using a highly sensitive calorimeter. This value is in very good agreement with the value predicted by a proposed model.Comment: 4 pages RevTex, 3 Postscript figures, to be published in Physical Review Letter

egg quality and productive performance of laying hens fed different levels of skimmed milk powder added to a diet containing lactobacillus acidophilus

Abstract The current trial was carried out on a commercial poultry farm to study the effect of skim milk powder (SMP) added to a diet containing Lactobacillus acidophilus on performance and egg quality of laying hens from 20 to 49 wk of age. A total of 2,400 Hy-Line W-36 laying hens were housed in 600 unenriched cages (4 hens each) located over 4 tier levels. Animals were assigned to 1 of 3 experimental treatments (0, 3, and 4). The laying hens assigned to treatments 3 and 4 received a diet enriched respectively with 3 and 4% SMP, whereas the animals in treatment 0 were fed a diet without SMP. All diets, moreover, were supplemented with L. acidophilus D2/CSL. Hen performance was determined throughout the experimental period and egg quality was measured on 30 eggs per treatment every week. Results showed that productive performance in terms of egg production, egg weight, and feed conversion ratio was not influenced by SMP at 3 or 4% of the diet. Egg quality was significantly affected by SMP included at 3 or 4% of the diet. Eggs from treatments 3 and 4, in fact, displayed higher shell thickness than those from treatment 0 (

Practice Recommendations for Diagnosis and Treatment of the Most Common Forms of Secondary Hypertension

The vast majority of hypertensive patients are never sought for a cause of their high blood pressure, i.e. for a \u2018secondary\u2019 form of arterial hypertension. This under detection explains why only a tiny percentage of hypertensive patients are ultimately diagnosed with a secondary form of arterial hypertension. The prevalence of these forms is, therefore, markedly underestimated, although, they can involve as many as one-third of the cases among referred patients and up to half of those with difficult to treat hypertension. The early detection of a secondary form is crucial, because if diagnosed in a timely manner, these forms can be cured at long-term, and even when cure cannot be achieved, their diagnosis provides a better control of high blood pressure, and allows prevention of hypertension-mediated organ damage, and related cardiovascular complications. Enormous progress has been made in the understanding, diagnostic\ua0work-up, and management of secondary hypertension in the last decades. The\ua0aim of this minireview is, therefore, to provide updated concise information on the screening, diagnosis, and management of the most common forms, including primary aldosteronism, renovascular hypertension, pheochromocytoma and paraganglioma, Cushing\u2019s syndrome, and obstructive sleep apnea