VETERINARSKI ARHIV 69 (4), 199-209, 1999

ISSN 1331-8055 Published in Croatia

Effect of probiotic on production results of fattened chickens fed different quantities of protein

Zeljko Mikulec¹*, Vlasta Serman¹, Nora Mas¹,
and Zdenko Lukac²

¹Department of Animal Nutrition, Faculty of Veterinary Medicine,
University of Zagreb, Zagreb, Croatia;

²Veterinary Station Đakovo d.o.o., Đakovo, Croatia

* Contact address:
Dr. Zeljko Mikulec,
Department of Animal Nutrition, Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, 10000 Zagreb, Croatia,
Phone: 385 1 23 90 273; Fax: 385 1 214 697; E-mail: zmikulec@mavef.vef.hr

MIKULEC, Z., V. SERMAN, N. MAS, Z. LUKAC: Effect of probiotic on production results of fattened chickens fed different quantities of protein. Vet. arhiv 69, 199-209, 1999.

ABSTRACT

The aim of this study was to evaluate the effects of added probiotic preparation Nutrigen^(r) on production results of fattening chickens fed on diets containing different levels of protein. The experiment was conducted on 280 sexed chickens (males and females, separately) through a 42-day fattening period. Diets used in the present experiment were differentiated with regard to quantities of protein and with the addition of probiotic Nutrigen^(r). The effects on production results were evaluated on body mass gain, feed conversion rate, amount of abdominal fat, carcass quality, body mass uniformity and health status. Chickens of both sexes in control groups fed with diets contained adequate amounts of protein achieved higher body mass gain than chickens in experimental groups that were fed the same diets but with the addition of Nutrigen^(r). The results show that probiotic added to diets with sufficient quantities of protein did not show any beneficial effects on production results. However, the effect of probiotic was manifested in diets with deficient quantities of protein.

Key words: nutrition, crude protein, probiotic, fattening chicks, production results

Introduction

Probiotic feed additives consisted of selected strains of Lactobacillus and Streptococcus that alter the microbial species present in the gastrointestinal system to the benefit of the treated animal. One example of such a beneficial effect of probiotic is suppression of Salmonella infections through the administration of mature micro-flora of the digestive system to a day-old fattening chicken (NURMI and RANTALA, 1973). Research on chickens has shown the gizzard to be a good source of the lactobacilli required for maintaining bacterial balance in the intestines (FULLER and TURVEY, 1971; FULLER and BROOKER, 1974), and can be found in the epithelium in the first day of life of a chick.

In addition to the stimulation of development of desirable bacteria, the probiotic effect of Lactobacillus is also manifested in the prevention of development of coli-bacteria and in its inhibition of enterotoxins in the digestive system (FULLER, 1977), which reduces the breakdown of proteins to nitrogen. In this way, the utilisation of proteins (amino acids) is improved, particularly from food that does not contain them in optimum quantities. This is supported by research results that demonstrate the favourable influence that probiotics have on the growth of body mass and feed conversion rate. However, the effect on body mass growth and food conversion is significantly better when the levels of methionine, cystine and lysine in feed are reduced (DILWORTH and DAY, 1978).

Growth and feed conversion of fattening chickens have not been improved by probiotic added into feed that contained all nutrients in optimal quantities (KOS and WITTNER, 1982b). Conversely, addition of probiotic to the feed of fattening chickens that contains no proteins (19.5% and 16.4% CP) sufficient for the optimum growth of chickens has a significant influence (P<0.01) on growth of body mass, increasing the meat yield of male chickens by 1.58% and of female chickens by 1.26% (KOS and WITTNER, 1982a). Every stress, regardless of its cause, can result in the increase of a number of undesirable micro-organisms (Staphylococcus, Streptococcus, Corynebacterium, Enterobacteriaceae) in digestive system of poultry, to the detriment of Lactobacillus (SUZUKI et al., 1989). This, of course, results in disrupted digestion and reduced feed utilisation, which in turn leads to a decline in production results and adversely effects health. Consequently, probiotics added to chicken feed can reduce the symptoms typical for intensive production. Probiotics generally are not expected to improve production results themselves, but their influence is manifested through a lower mortality rate due to the elimination of some pathogens from the intestinal tract. The application of probiotics increases resistance level and can improve the health, growth and feed conversion rate of chickens (GERENDAI, 1993).

In contrast to intestinal grafts, certain probiotics are inactivated and, to a certain degree, degraded yeasts (for example, Ascogen, Nutrigen^(r), etc.). The influence of Probioticum S probiotic on the immunological response of chickens to the vaccine against Newcastle disease has been studied by RAMADAN et al. (1991). They discovered significantly higher values of specific haemagglutination inhibition titre in the serum of chickens receiving Probioticum S with their feed in comparison with a control group of chickens.

During the course of a research conducted by VIDUC (1997) three groups of fattening chickens consumed feed to which 0.05%, 0.10% and 0.15% of Nutrigen^(r) was added. Compared with a control group the addition of 0.10% of probiotic proved to be the most favourable with regard to the development of bursa of Fabricius, the most significant organ in the immunological system. The same quantity resulted in a significant reduction in the quantity of abdominal fat in relation to those chickens not receiving the probiotic.

The aim of this study was to evaluate the effects of added probiotic preparation Nutrigen^(r) on production results of fattening chickens fed on diets with different levels of protein.

Materials and methods

Animals and diets

The research was conducted on 280 sex-differentiated Avian 24 K line broiler chickens. On the first day of the experiment, one-day-old chicks were weighed and divided into four male and four female groups (35 birds each) with a similar body mass. Throughout the 42 days of the experiment all groups were kept in cages for fattening and under identical micro-climatic conditions, suited to that specific line of chickens. The health condition of the chickens was monitored on the basis of the clinical picture and patho-anatomical findings in dead birds.

The effect of Nutrigen^(r) was studied. Nutrigen^(r) (Chemoforma AAG, Basel, Switzerland) is a probiotic preparation prepared from oligonucleotides created through the autolysis of yeasts Saccharomyces cerevisiae which, to a considerable degree, are resorbed from intestines. According to product details provided by the producer, Nutrigen^(r) acts in the tissues, affecting the enzyme systems of cells and partially preventing the breakdown of proteins, thus improving their utilisation, as well as having an indirect influence on the more favourable relations of flesh and fatty tissue. Nutrigen^(r) was added into the feed for experimental groups of chicks E₁ (E₁-m, E₁-f) and E₃ (E₃-m, E₃-f) in amounts of 0,10%.

Throughout the whole research period the chickens consumed food and water ad libitum. For the first three weeks they were fed on a starter mixture, and for the final three weeks they received a finisher mixture. The feed used in the research differed in quantities of proteins and in the addition of Nutrigen^(r). The control group of male and female birds (C-m, C-f) was fed on a commercial starter (21% of crude proteins, CP) and a finisher (18% CP), without the addition of Nutrigen^(r).

Identical commercial feed mixtures, but with Nutrigen^(r) added, were used in feeding of experimental groups E₁-m and E₁-f.

Experimental groups E₂-m and E₂-f were fed on mixtures with insufficient quantities of proteins (starter 18% CP, finisher 16% CP) and without the addition of Nutrigen^(r), while groups E₃-m and E₃-f consumed feed identical in content but with the addition of Nutrigen^(r). Nutritive value and chemical composition of the feed mixtures are given in Table 1.

Table 1. Nutritive value and chemical composition of feed mixtures used in the trial with chickens (C=control group, E=experimental groups)

*0.1% Nutrigen^(r); **Official methods were used troughout ANON. (1984);
***Values of amino acid were calculated

Measuring of production results

The influence of probiotics added to commercial mixtures, and mixtures with a protein quantity insufficient to achieve good production results with fattening chickens of the Avian K24 line, was determined on the basis of values of body mass gain, feed conversion, participation of abdominal fat in the carcass and in the living mass of chickens, uniformity of body mass, and on the health condition of the chickens.

Control of body mass was carried out every 7 days by individual weighing of all chickens following a 12-hour fasting period. Food consumption was recorded daily in order to determine weekly and overall food conversion.

Participation of abdominal fat in living mass and carcass mass was determined at the end of the research in 10 female and 10 male chickens from the control and test groups.

The health condition of the chicks was assessed clinically, and from pathoanatomical findings in dead animals.

Chicks in all groups were vaccinated against Newcastle disease in the usual manner.

Statistical analysis

Data regarding the uniformity of the body mass of chickens at the end of the fattening period were obtained by the relative measure method, i.e., on the basis of the variation coefficient expressed in percentages and presented together with the average mass of chickens, the standard deviation of average body mass and the variation coefficient for the control groups and test groups of male and female chickens.

All results were subjected to statistical analysis (SPATZ, 1997). The mean values of measured indices of each experimental group were compared with corresponding values of the control group; the significance of differences was assessed by Student^'s t-test (P<0.05).

Results

The body mass of all chicks was checked every seven days. Table 2 presents average body mass on the 1^st day of trial, 21^st day (last day of feeding starter) and on the 42^nd day (last day of feeding finisher and the termination of the trial).

Table 2. Average body mass (g) in control (C) and experimental (E) groups of chicks on the 1^st day of trial, 21^st day (last day of feeding starter) and on the 42^nd day (last day of feeding finisher and the termination of the trial)

N=number of chicks; M=mean value of body mass; SD=standard deviation; VC=variation coefficient (%); m=male; f=female

Average values of body mass gain and feed conversion in the first (starter), and second (finisher) phases of fattening, as well as total values, are shown in Table 3.

Table 3. Average body mass gain (g) of chickens (C=control group, E=experimental groups) and feed conversion (kg/kg)
during the trial (N=10 per group)

m=male; f=female

The abdominal fat shares in the live mass and in carcass were observed as additional indicators for evaluation of effects of probiotics Nutrigen^(r) on production results of fattened chickens fed different quantities of proteins (Table 4).

Table 4. Average abdominal fat in the control (C) and experimental (E) groups of chicks (N=10 per group)

m=male; f=female

Data on uniformity of the flock (average final body mass of chicks) are shown in Table 5 and were obtained by means of relative measure; variability coefficient is expressed as a percentage.

Table 5. Uniformity of body mass of control (C) and
experimental (E) groups of chicks

N=number of chicks; M=mean value of body mass (g); SD=standard deviation;
VC=variation coefficient (%); m=male; f=female

Discussion

The influence that addition of Nutrigen^(r) to feed mixtures had on body mass growth depended on the quantity of proteins. Chickens of both sexes (C-m and C-f) in control groups (Table 3) achieved higher body mass growth (1951 g and 1671 g) in relation to chickens in test groups E₁-m (1929 g) and E_l-f (1662 g), which received feed mixtures of the same composition but with the addition of Nutrigen^(r). The difference in growth was not statistically significant (P>0.05), which indicates the absence of any effect of Nutrigen^(r) in feed mixtures of optimum composition. Similar results were achieved in a number of previous investigations (KOS and WITTNER 1982a; DURST et al., 1995) where probiotic added in trial diets with sufficient quantity of proteins did not show significant beneficial effects on production results. This can be explained by the well-known probiotic action of decreasing the degradation rate of amino acids. Therefore, the effect of probiotic addition is more obvious in cases of lack of proteins.

In contrast, the full probiotic effect on body mass growth was manifested in test groups E₃-m (2041 g) and E₃-f (1731 g) receiving feed mixtures deficient in proteins, but with the addition of Nutrigen^(r). Average values of body mass growth were significantly higher in comparison with all other groups of chickens (P<0.05). An insufficient quantity of proteins without the addition of Nutrigen^(r) resulted in the lowest body mass growth in chickens in test groups E₂-m (1870 g) and E₂-f (1696 g). Similar results with fattening chickens were obtained by KOS and WITTNER (1982a). In their research the probiotic preparation Probioticum^(r) showed its full effect only when added to chicken feed deficient in methionine (0.37%), lysine (0.91%) and tryptophan (0.21%). The authors state that 48-day-old male chicks in the test group were heavier by 20 g, and female chicks by 60 g, in relation to male and female chicks in the control group. The same authors (KOS and WITTNER, 1982b) also noticed that such beneficial effect did not occur when Probioticum^(r) was added to feed mixture that contained all necessary nutrients and biologically active substances. DILWORTH and DAY (1978) conducted a research into the influence that the addition of Lactobacillus to the feed of fattening chickens had on body mass growth and on feed conversion. A favourable effect was achieved only when the level of methionine and cystine amounted to 90% of required values. When added to feed containing sufficient quantities of the above-mentioned amino acids, the Lactobacillus culture was not effective.

Throughout the entire period of our research, total feed conversion was highest in the control group of female chickens (C-f=2.21 kg/kg). In the test group of female chickens fed on feed mixtures with the same quantity of proteins, but with the addition of Nutrigen^(r), feed conversion was improved by 12.7% (E₁-f=1.96 kg/kg). Groups of female chickens fed on protein-deficient feed, with or without the addition of probiotic, showed an 8.8% (E₂-f=2.03 kg/kg) and 9.9% (E₃-f=2.01 kg/kg) better feed conversion in relation to the female control group. These differences are statistically significant (P<0.05). In contrast, feed conversion throughout the fattening period of male chickens was lowest in the control group (C-m=1.92 kg/kg), but the differences with regard to all test groups of chickens were not statistically significant (P>0.05). The research conducted by VIDUC (1997) demonstrated the favourable influence of the addition of Nutrigen^(r) to the feed of fattening chickens (0.05%, 0.10% and 0.15%) on feed conversion values. Favourable effects were proportional to the quantity of probiotic added, but the research involved only male chickens.

In their research, PISARSKI and WÓJCIK (1993) observed no significantly beneficial effect of probiotic addition to chicken feed on feed conversion. They tested the addition of probiotic on fattening chickens fed on feed based on barley and triticale. SEFTON (1990) researched the effect that different probiotics (Acid Pak 4-Way and Lacto-Sacc) added to the feed of broiler chickens had on final body mass, feed conversion and mortality rate in the course of fattening. The given parameters in test groups were significantly better in relation to the control group. Investigating the effects of the addition of Lacto-Sacc to the feed of fattening chickens, GIPPERT (1991) found that treated chickens had a 3% greater final body mass and lower feed conversion compared to untreated chickens.

In our research the quantity of abdominal fat and its participation in the carcass and in the living mass of female chickens is significantly higher (P<0.05) in comparison to male chickens. An insufficient quantity of proteins in mixtures fed to fattening chickens resulted in a significant increase of fat in the carcass and in the living mass of both sexes (P<0.05). Addition of Nutrigen^(r) to feed containing sufficient quantities of proteins had no significant effect on the reduction of abdominal fat in female chickens. However, in group E₁-m the percentage of fat was 7.4% lower in the carcass and 20.4% lower in the living mass in comparison to group C-m (P<0.05). The addition of Nutrigen^(r) to feed with insufficient quantities of proteins reduced the percentage of abdominal fat in carcass of chickens of both sexes and in the living mass of female chickens (P>0.05). Similar results were obtained by MICAN (1978), PISARSKI and WÓJCIK (1993) and VIDUC (1997).

According to the variability coefficient calculated at the end of the experiment (Table 5), uniformity of body mass did not show significant differences between chickens fed the same diets, with or without addition of probiotic (P>0.05). In female chickens the variability coefficients were lower in groups fed on feed mixture deficient in proteins (E₂-f=6.69% and E₃-f=7.45%) compared to groups fed on feed with a sufficient quantity of proteins (C-f=9.11% and E₁-f=8.42%), while the addition of Nutrigen^(r) did not bear any significant influence on the variation coefficient. Differences within a flock of male chickens were at their widest in the test group of chickens (E₁-m=11.27%) which consumed feed containing sufficient quantities of proteins and added probiotic. In other groups the variability coefficient ranged between 8.62% and 9.38%.

CHAPMAN (1988), however, found that probiotics had a significantly beneficial influence on flock uniformity. He carried out his research on young breeding chickens aged between 7 and 14 weeks, and established that the addition of probiotic to the feed of test groups of breeding chickens had a significant influence on the uniformity of their body mass.

Total mortality rate for the entire period of the research was 6.07% (17 chickens). Mortality rates for different groups were, respectively: C-m 8.57%; C-f 8,57%; E₁-m 14.29%; E₁-f 2.86%; E₂-m 5.71%; E₃-m 8.57%. No instances of death were recorded in E₂-f and E₃-f groups of chickens. The obtained results relating to the demise of chickens in control and test groups do not indicate any links between the quantity of proteins and the addition of probiotic to chicken feed, and their deaths. Causes of death according to pathoanatomical findings were: traumatic liver rupture, rachitis, arthritis suppurative, enteritis catarrhalis, sepsis, stunted growth, etc.

References

ANONYMOUS (1984): Official Methods of Analysis (14^th ed.). Association of Official Analytical Chemists. Arlington, VA, USA.

CHAPMAN, J. D. (1988): Probiotics, acidifiers and yeast culture: A place for natural additives in pig and poultry production. Biotechnology in the feed industry. Alltech Technical Publications. Nicholasville, Kentucky. pp. 219-233.

DILWORTH, B. C., E. J. DAY (1978): Lactobacillus cultures in broiler diets (S. A. A. S. Abstract). Poultry Sci. 57, 1101.

DURST, L., H. H. FRIEDRICHS, B. ECKEL (1995): The nutritive effect of Saccharomyces cerevisiae on fattening and carcass performance of broilers. Arch. Geflügelk. 59, 322-327.

FULLER, R., A. TURVEY (1971): Bacteria associated with the intestinal wall of the fowl (Gallus domesticus). J. Appl. Bact. 34, 617-629.

FULLER, R., B. E. BROOKER (1974): Lactobacilli which attach to the crop epithelium of the fowl. Amer. J. Clin. Nut. 27, 1305-1312.

FULLER, R. (1977): The importance of lactobacilli of maintaining normal microbial balance in the crop. Brit. Poult. Sci. 18, 85-94.

GERENDAI, D. (1993): Lacto-Sacc and Yea-Sacc preparation in the feed of New-Hampshire parent flock. 9^th European Symposium on Poultry Nutrition. Jelenia Góra. Poland. pp. 379.

GIPPERT, T. (1991): Effect of Lacto-Sacc or De-Odorase on broiler performance. Biotechnology in the feed industry. Proceedings of Alltech's Seventh Annual Symposium. Alltech Technical Publications. Nicholasville, Kentucky. pp. 405-406

KOS, K., V. WITTNER (1982a): Effect of probiotics on growth, feed conversion and performance of chicks receiving protein-deficient diet. Praxis vet. 30, 355-359.

KOS, K., V. WITTNER (1982b): Use of probiotics in the nutrition of the fattening chicks. Praxis vet. 30, 283-286.

MICAN, P. (1978): Effect of Probioticum on growth and health of fattening chickens. Preliminary report. Stanice Veterinarni Pece, Hustopece u Brna, CSSR.

NURMI, E., M. RANTALA (1973): New aspects of Salmonella infection in broiler production. Nature 241, 210-211.

PISARSKI, R. K., S. WÓJCIK (1993): Some productive effects of broiler chicks given barley and triticale supplemented with probiotics. 9th European Symposium of Poultry Nutrition, Jelenia Góra, Poland. pp. 382-385.

RAMADAN, A., R. SOLIMAN, N. A. AFIFI, I. REDA (1991): Studies on factors influencing immune response in chickens. V Effect of Probioticum "S" on the immune response of chickens to Newcastle disease virus vaccine. J. Egypt. Vet. Med. Ass. 51, 409-425.

SEFTON, T. (1990): The probiotic concept and poultry production: evaluating performance data. European Lecture Tour. Alltech Technical Publications.

SPATZ, C. (1997): Basic Statistics. 6^th ed. Brooks/Cole Publishing Company. Pacific Grove, California.

SUZUKI, K., Y. KODAMA, T. MITSUOKA (1989): Stress and intestinal flora. Bifidobacteria Microflora 8, 23-38.

VIDUC, D. (1997): The influence of probiotic Nutrigen(r) to the deposition of abdominal fat in broiler chickens. M.Sc. Thesis. Faculty of Veterinary Medicine, University of Zagreb. Zagreb.

Received: 24 June 1999
Accepted: 18 October 1999

MIKULEC, Z., V. SERMAN, N. MAS, Z. LUKAC: Ucinak probiotika na proizvodne rezultate pilica u tovu hranjenih razlicitim kolicinama bjelancevina u obroku. Vet. arhiv 69, 199-209, 1999.

SAZETAK

Cilj istrazivanja bio je utvrditi ucinak probiotika Nutrigen^(r) na proizvodne rezultate pilica u tovu hranjenih obrocima s razlicitim kolicinama bjelancevina. Pokusni tov u trajanju od 42 dana proveden je na ukupno 280 tovnih pilica odvojenih po spolu. Koristeni obroci razlikovali su se u svezi s kolicinom bjelancevina i dodatkom probiotika. Ucinci probiotskog pripravka Nutrigen^(r) ustanovljeni su na prirastu tjelesne mase, konverziji hrane, kolicini trbusne masti, randmanu, ujednacenosti tjelesne mase i zdravlju pilica. Pilici oba spola u kontrolnim skupinama hranjeni obrocima koji su sadrzavali optimalne kolicine bjelancevina polucili su bolje priraste tjelesne mase u odnosu na pilice pokusnih skupina koji su hranjeni obrocima iste hranidbene vrijednosti, ali uz dodatak probiotskog pripravka. Medutim, izrazenije povoljno probiotsko djelovanje ustanovljeno je u pilica koji su probiotik Nutrigen^(r) primali u obrocima s nedovoljnom kolicinom bjelancevina.

Kljucne rijeci: hranidba, sirove bjelancevine, probiotik, pilici u tovu, proizvodni rezultati