FEED Business Worldwide March, 2012
The impact of sodium butyrate on broiler performance
by J.J. MALLO1*, M. PUYALTO1 and S.V. RAMA RAO2
1* Norel S.A., C/ Jesús Aprendiz 19, 1º A, 28007, Madrid, Spain;
2 Project Directorate on Poultry, Rajendranagar, Hyderabad 500 030, Andhra Pradesh, India
When enhanced by essential oils, sodium butyrate provides proven bactericide effects against both gram negative (Fernández-Rubio, 2009) and gram positive (Jerzsele, 2011) bacteria, along with a number of beneficial physiological effects on the animal (Guilloteau, 2010).
Hypothesis
The effects on animal performance can be summarized as follows: Control of the intestinal barrier, pathogen reduction, increase of mucin synthesis, along with better immune response and regulation. Sodium butyrate's effects on the intestinal epithelium are as follows: Better controlling of cellular apoptosis (via reducing the normal cell degradation and increasing the rate of malign cell degradation), enhanced energy supply for colonocytes and enterocytes (under ATP form) and the optimisation of intestinal cells proliferation, differentiation and maturation (Guilloteau, 2010).
The better development of the intestinal epithelium creates a larger intestinal surface area that will be in contact with the feed bolus, thus resulting its better digestion (Pluske, 1996). In such a way, the use of sodium butyrate in broiler chickens will result in animals with a well developed intestinal ephitelium that make them better digest the feed that they receive. This diet digestibility improvement may explain the reduction in feed conversion rate that is normally observed with the use of sodium butyrate (Mallo, 2010).
Materials & methods
Animals and handling: 750 one day old Cobb 400 broilers were randomly distributed in 30 groups of 25 animals each (10 replicates per treatment). The animals were identified with bands in the wings and housed in raised wire-floored stainless steel battery brooder pens in open sided poultry shed.
The room temperature was kept at 35±0.5°C up to the 7 days age, and was progressively decreased to 27±1°C at 21 days of age, after which, the animals were kept at room temperature (25oC to 33oC). The animals were vaccinated against Newcastle and infectious diseases of the bursa as per normal vaccination schedule.
Diets: Feed based on corn and soybean meal were administered with values of metabolic energy of 2,950, 3,050 and 3,150 kcal of energy and 230g, 210g and 190g of crude protein per kg, respectively, during the pre-starter (1-11 days), starter (12-21 days) and finisher (22-42 days) stages (see Table 1).
Lysine, methionine and threonine concentrations are also showed in Table 1. These diets were supplemented with sodium butyrate (BUT) (Gustor, Norel Animal Nutrition, Spain) at 3 different concentrations: 0mg/kg, 500mg/kg and 1000g/kg respectively. Each diet was administered ad libitum to 10 replicates of 25 animals per replicate assigned following a totally randomized design.
Parameters under evaluation
Development: Weekly weight and consumption measurements were taken per replicate up to 42 days of age. Using these data, the average daily growth, average daily feed consumption and feed conversion ratio (FCR) were calculated for each replicate.
Carcass traits: At 42 days of age, one animal from each replica was chosen such that it fell within the average finishing weight in its group (+5%), and was slaughtered through cervical dislocation to evaluate the carcass traits.
Post-slaughter, the following observations were taken: Weights of ready-to-cook (dressing) yield (with liver, gizzard and heart), breast weight, liver, gizzard and abdominal fat were recorded and expressed as the relative percent to the pre-slaughter live weight of the respective bird.
Energy and protein digestibility: A metabolic trial was conducted at 40 to 42 days. A total of 36 animals were randomly extracted from 12 replicas (3 animals from each replica; 4 replicas per treatment), and were placed in metabolic cages after weight and consumption control.
For energy and protein digestibility evaluation, the following data was taken for each cage: Dry matter of the total feed consumption (consumption) and dry matter excreted (excreted). The energetic concentration of the feed samples and excreted matter was evaluated (calorimetric bomb) as well as the brut protein (AOAC, 2005). The difference among consumption and excreted matter was used to calculate the retention of energy and protein.
Gut villi growth: The development of intestinal villi was quantified by scanned electron microscopy (SEM) following the methodology described by John et al. (1998). The procedure includes collection of a 5mm2 piece of duodenum at the loop (at both 21 and 42 days of age) and fixation within 2.5% gluteraldehyde of a aphosphate buffer 0.1M (pH 7.2) for 24 hour at 4oC and post fixing in a 2% aqueous osmium tetroxide for 4 hours.
The tissue was subsequently dehydrated in a series of graded alcohol concentrations and dried to its critical point with a CPD unit. Processed samples were mounted with double sided carbon conductivity tape. A thin layer of gold coat over the sample was smeared by using an automated sputter coater (model JEOL – JFC-1600) for 3 minutes. Samples were scanned under a Scanning Electronic Microscope (model: JOEL-JSM 5600).
Statistical Analysis: One-way analysis of variance was carried out following completely randomized design (Snedecor and Cochran, 1989). Treatments were compared using Ducan's multiple range test (Duncan, 1955), setting the significance at P<0.05.
Results & discussion
Productive data: Table 2 shows the results for weight, growth, consumption and conversion rates of the broilers. Productive data were not affected by the use of sodium butyrate in the diet.
Slaughterhouse Parameters: Equally, sodium butyrate had no impact on slaughterhouse parameters, as it is shown in Table 3.
Nutrient Digestibility: Sodium butyrate supplement, in both amounts, significantly increased the animal's energy retention. However, sodium butyrate did not produce a linear effect, as there were no differences among the inclusion levels of the salt of the organic acid.
Equally, protein retention was also better in animals receiving sodium butyrate in the diet; in this case, there were differences among butyrate levels of the feed: protein digestibility was higher in animals receiving 1,000 mg of sodium butyrate per ration kilogram than for the ones receiving 500 mg/kg.
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