Evaluation of a probiotic and an acidifier as an alternative to the use of antibiotic growth promoters in broilers

Introduction

Since January 2006, there is a total banning of antibiotic growth promoters (AGP) in animal feeding in the European Union (EU). Despite being a controversial subject because there is both, information for and against it, the Scientific Steering Committee of the European Commission proposed a ban on AGP based on the "precautionary principle". As of 2012 the use of salinomycin and monensin will also be prohibited, currently used as coccidiostats (Cepero Briz, 2005).

Other factors related to feeds, in addition to prohibiting the use of AGP, would act as aggravating factors. For example, in 2001, the EU banned the use of meat and bone meals, thus increasing the use of soybean meal and the risk of anti-nutritional factors when it is not properly processed. The ban has also stimulated a greater level of inclusion of oils and fats, which may predispose to enteric problems (Cepero Briz, 2005).

Since the ban on the use of AGP, a resurgence of certain diseases such as necrotic enteritis (NE) caused by Clostridium perfringens types A and C, has been observed. NE is a multifactorial disease and its incidence depends on nutrition, management (poor environmental conditions, high stocking densities), health (very short health gaps), among others (Santomá et al., 2006).

As a result of this type of pathologies an average increase in mortality, lower weight, increased conversion rates and less homogeneous flocks were observed.

As an alternative to AGP, different products have emerged such as probiotics and acidifiers, among others. In order to evaluate this type of additives, experimental methodologies have been developed based on generating challenge conditions (Iglesias et al., 2011).

Objective

To evaluate the effect of inclusion of BioPro^® and AES^® sodium-enriched acidifier in broiler chicken diets on the performance of challenged birds.

Materials & Methods

A total of 576 male Cobb 500 broilers housed on the floor on wood ss litter were used. Four treatments were evaluated (Table 1) with 8 replicates of 18 birds each, arranged in a randomized complete block design using the Duncan test for mean separation (InfoSTAT^®,2001).

Table 1. Treatments

Treatments	Description
1.- Control +	Basal + BMD 11% (540 g/ton)
2.- Control -	Basal without ATB
3.- BioPro^®1	Idem T2 + BioPro 2 L/ton up to 14 d, then 1 L/ton
4.- AES²	Idem T2 + AES 2 kg/ton

^{1Probiotic based on a strain of Enterococcus faecium; 2Acidifier enriched with sodium. BMD: Bacitracin methyl disalicylate 11%.}

The feeding program was: Starter (1 - 7 days), Grower (8 - 28 days), Finisher (29 - 43 days) and Last week (44 - 49 days) (Table 2) and feed was supplied as a meal. Diets were formulated based on the recommendations of Cobb using the DAPP software.

N-utrition^® 2.0 (2003).

Table 2. Composition and nutrient contribution of diets

Age (Days)	1 - 14 days	15 - 28 days	29 - 42 days	43 - 49 days
Corn	61.03	65.48	66.66	69.96
Soybean meal 44	24.97	16.26	17.83	7.78
Soybeans, Steam	6.60	11.10	8.86	15.55
Meat meal 41	6.34	6.16	5.74	5.80
Shell	0.43	0.42	0.41	0.41
Salt	0.33	0.26	0.25	0.24
Methionine	0.05	0.07	0.08	0.08
Premix	0.20	0.20	0.15	0.15
Choline	0.05	0.05	0.03	0.03
Nutrients (%)
TME (Kcal/Kg)	3288	3383	3476	3476
Lipids	4.64	5.35	6.23	6.03
Protein	21.00	19.00	18.00	17.00
Lysine	1.10	0.97	0.91	0.84
Methionine + Cystine	0.71	0.67	0.65	0.62
Threonine	0.80	0.71	0.67	0.63
Arginine	1.40	1.25	1.17	1.08
Ca	1.00	0.96	0.90	0.90
P Av.	0.50	0.48	0.45	0.45

^{Coccidiostat was not used because the chickens were challenged with coccidia oocysts.}

Challenge
In order to be in an area of a greater animal production response to any change in nutrient absorption, methionine + cystine, lysine and threonine requirements were lowered to 80% of the recommendation of the farm and consequently synthesis amino acid inclusion was reduced in all feeds.

On the third day of life, chicks were vaccinated with coccidia oocysts using 5 times the manufacturer recommended dose. Litter of previous production cycles was also used and to raise bacteria counts, it was sprayed with a solution containing 10⁹ CFU/ml of E. coli (20 ml of this solution every 1.8 m² brought to 50 ml with saline 0.9% w/v). This operation was performed on 3 occasions throughout the production cycle (7, 14, and 21 days). Litter moisture was maintained by sprinkling 500 ml of water per pen every other day while brooders were burning.

Measurements

Body weight, feed intake adjusted for mortality, calculated feed conversion and weight/conversion ratio were determined on a weekly basis.

Results & Discussion

Tables 3 to 6 and Figure 1 show results obtained.

Table 3. Consumption (g)

Treatments	Days
7	14	21	28	34	42	49
1.- Control +	81	428	976	1869^AB	2844^B	4376^B	5894
2.- Control -	86	434	961	1855^B	2803^B	4346^B	5855
3.- BioPro^®	86	437	979	1847^B	2897^A	4475^A	6022
4.- AES^®	82	429	977	1902^A	2880^A	4445^A	5997
CV%	5.1	4.8	1.6	2.4	2.6	2.4	2.9
Probability	0.29	0.92	0.19	0.10	0.09	0.08	0.20

^{Means in the same column with different superscript differ significantly (p≤0.10).}

Table 4. Weight (g)

Treatments	Days
7	14	21	28	34	42	49
1.- Control +	112	344	647^ab	1131^ab	1616^a	2292^ab	2890^AB
2.- Control -	111	347	633^c	1110^c	1667^b	2243^b	2816^B
3.- BioPro^®	112	351	641^bc	1151^a	1634^a	2342^a	2931^A
4.- AES^®	108	353	656^a	1154^a	1616^a	2308^a	2902^A
CV%	3.8	5.1	1.9	1.6	2.5	2.4	3.0
Probability	0.67	0.90	< 0.01	< 0.01	0.02	0.01	0.09

^{Means in the same column with different superscript differ significantly (small letter p≤0.05; capital letter p≤0.10).}

Table 5. Conversion

Treatments	Days
7	14	21	28	34	42	49
1.- Control +	0.726	1.246	1.509^AB	1.652	1.761	1.909	2.040
2.- Control -	0.770	1.250	1.520^A	1.671	1.789	1.938	2.080
3.- BioPro^®	0.766	1.247	1.519^A	1.655	1.772	1.911	2.055
4.- AES^®	0.756	1.214	1.491^B	1.649	1.783	1.926	2.067
CV%	3.7	2.7	1.4	1.9	1.9	1.8	1.6
Probability	0.18	0.44	0.06	0.54	0.38	0.33	0.15

^{Means in the same column with different superscript differ significantly (p≤0.10).}

Table 6. Weight/Conversion

Treatments	Days
7	14	21	28	34	42	49
1.- Control +	153	277	429^ab	686^a	918^a	1202^ab	1417^A
2.- Control -	145	279	417^b	665^b	876^b	1158^b	1354^B
3.- BioPro^®	146	282	423^b	696^a	923^a	1226^a	1427^A
4.- AES^®	143	291	440^a	700^a	908^ab	1199^ab	1405^A
CV%	5.4	6.5	3.0	2.6	3.7	3.5	3.9
Probability	0.40	0.70	0.01	< 0.01	0.05	0.03	0.07

^{Means in the same column with different superscript differ significantly (small letter p≤0.05; capital letter p≤0.10).}

Graph 1. Percentage ratio of different treatments with respect to the Positive Control (100%) at 49 days of life

Evaluation of a probiotic and an acidifier as an alternative to the use of antibiotic growth promoters in broilers - Image 1

Challenge model

No differences in feed consumption were observed between Negative Control and Positive Control.
Live weight of birds fed the negative control diet was lower than that of birds in the positive control group. Such differences were significant between 21 and 34 days (p< 0.05).
No differences in conversion between controls were observed.
The weight/conversion ratio was lower in the negative control with significant differences at 28 and 34 days (P< 0.05) and 49 days (P< 0.10).

These results show that the challenge model used affected bird performance, which is necessary to compare the effect of the tested additives.

BioPro^®

No differences in production response between birds fed with BioPro^® and BMD (positive control) were observed.
Feed consumption observed with BioPro^® was greater than with the negative control, significant differences (P< 0.10) at 34 and 42 days.
The weight reached with BioPro^® was greater with respect to the negative control group, with significant differences (P< 0.05) from the 28 days to 42 days. The same trend (P< 0.10) was observed at 49 days.
No differences in feed conversion were observed between BioPro^®and the Negative Control.
Response in terms of the weight/conversion ratio was similar to that described for weight.

AES^®

No differences in production response between birds fed with AES^® and BMD (positive control) were observed.
No differences in feed consumption were observed between birds fed with AES^® and the negative control.
Body weight obtained with AES exceeded Negative Control from 21 days to 42 days (P < 0.05).
There was a trend (P< 0.10) to a better conversion with AES observed at 21 days.
The weight/conversion ratio achieved with AES exceeded that of the negative control, with significant differences (P< 0.05) at 21 and 28 days and a trend (P< 0.10) at 49 days.

Conclusions

The challenge model applied negatively affected bird performance.
Results show that with the inclusion of BioPro^® or AES^® this situation can be reverted, which positions these additives as alternatives to antibiotic growth promoters.

References

Cepero Briz R. 2005. Retirada de los antibióticos promotores de crecimiento en la unión europea: causas y consecuencias. En XII Congreso Bienal Asociación Mexicana de Nutrición Animal (AMENA) Puerto Vallarta, Jalisco. URL:http://www.wpsa-aeca.es/aeca_imgs_docs/24_01_30_
MEXICO05-RCB.pdf. Acceso: 01/04/11.

DAPP, N-utrition. 2003. Software para formulación de raciones a mínimo costo. Versión 2.0. Colón, Entre Ríos, Argentina.

Iglesias BF, Azcona JO, Charriere MV, Lago C. 2011. Effect of BioPro on broiler chickens performance. pp 58. In: Proceeding of the International Poultry Scientific Forum, 24 y 25 de enero de 2011. Atlanta, GA, USA.

InfoSTAT. 2008. Software estadístico. Versión 2008p para Windows^®. Córdoba, Argentina.

Santomá G, Pérez de Ayala P, Gutiérrez del Alamo A. 2006. Producción de broilers sin antibióticos promotores del crecimiento. Conocimientos actuales. En XLIII Simposio Científico de Avicultura, Barcelona, España. URL:http://www.wpsa-aeca.es/aeca_imgs_docs/wpsa11617
71886a.pdf. Acceso: 01/04/11.

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