INCLUSION OF A SPECIES-SPECIFIC PROBIOTIC OR CALCIUM DIFORMATE IN YOUNG CALVES DIETS: EFFECTS ON GUT MICROBIAL BALANCE, HEALTH STATUS AND GROWTH PERFORMANCE
Tesi di Dottorato
Data di Pubblicazione:
2013
Citazione:
INCLUSION OF A SPECIES-SPECIFIC PROBIOTIC OR CALCIUM DIFORMATE IN YOUNG CALVES DIETS: EFFECTS ON GUT MICROBIAL BALANCE, HEALTH STATUS AND GROWTH PERFORMANCE / S. Maroccolo ; director: V. Bontempo ; coordinator: G. Savoini ; tutor: A. Agazzi. UNIVERSITA' DEGLI STUDI DI MILANO, 2013 Feb 19. 25. ciclo, Anno Accademico 2012. [10.13130/maroccolo-serena_phd2013-02-19].
Abstract:
ABSTRACT
Calf morbidity and mortality represent major financial losses for veal and dairy producers, especially intestinal bacterial infections are the primary causes of calf mortality. Thus the preventive intervention is a recommended strategy and as a prior measures probiotics and acidifiers is an alternative to the use of antibiotics. Probiotics play a critical role in the completeness and immune response of the intestinal mucosa while the main mode of action of organic acids is through their bacteriostatic and bactericidal action. The purpose of the present trials was the evaluation of the effects both a species-specific probiotic administration in veal (1st trial) and dairy calves (2nd trial) than an acidifier supplementation in veal calves (3rd trial) on health status, gut microbial balance and growth performance. On veal calves the effects of probiotic and acidifier on slaughter performance and histological survey were further evaluated.
The aim of first the study was to evaluate the effects of the administration of a species-specific probiotic supplement to veal calves on performance and microbial parameters in standard rearing conditions. Ninety six male Friesian veal calves (49.31 ± 1.38kg of body weight and 20±5 days of life) were divided at random in two homogeneous groups of 48 animals each from the arrival in the farm and fed either a basal diet (C) or a basal diet plus 1.8x109 CFU/head/day of a probiotic supplement containing Bacillus coagulans, Lactobacillus animalis and Lactobacillus paracasei spp. paracasei in a 35:30:35 ratio (T) for a total of 180 days. Starting from 10th day from arrival and monthly until the end of the trial, individual body weight (BW) was recorded and average daily gain (ADG) was computed. At the same time, on the half of animals per group, faecal samples were collected for faecal score evaluation (FS), Lactobacilli count, Escherichia coli count and Lactobacilli/E.coli ratio, while blood samples were collected for haematological, haematochemical and immunological parameters evaluation. During the whole experimental period daily health status and therapeutic treatments were recorded for General Health Score (GHS) determination. At slaughter 10 animals per group were analysed for macroscopically injuries detection, and gut samples were collected for histological analyses. On each subject carcass weight, dressing percentage, fattening condition, carcass grade (SEUROP classification) and meat pH were recorded. During the trial were considered six times (corresponding to the each month of fattening): from time 0, referred to the 10th day from arrival, to the last considered month (time 6). BW resulted significantly higher (P≤0.05) in C calves than T at the 5th (C=226.76kg vs T=223.27kg) and 6th (C=267.14kg vs T=263.56kg) considered times while ADG was not different between groups. Faecal consistency was, significantly higher in T group at the 4th sampling (P≤0.01) as faecal Lactobacilli content (C=8.37 Log10 vs T=8.49 Log10; P≤0.05). This trend could explain the better GHS observed in supplemented calves during the trial.
At different times, some haematological parameters such as basophils, aspartate amino transferase (AST), bilirubin, glucose, urea, bactericidal and complement were higher (P<0.05) in C group, while non-esterificated fatty acids (NEFA) and lactate dehydrogenase (LDH) showed lower values than T (P<0.05).
At slaughter no differences were observed for carcass weight, dressing percentage, carcass grade and meat pH. The cecum histological examination revealed a less evident de-epithelialisation and a greater integrity of the epithelium surface in T subjects than C, while in both the ileum than in cecum a numerical increase of the intestinal crypts’ depth was det
Tipologia IRIS:
Tesi di dottorato
Elenco autori:
S. Maroccolo
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