Effect of yeast culture supplementation on carcass yield and humoral immune response of broiler chicks.

Aim: A study was conducted to evaluate the effect of supplemental yeast culture (Diamond V XPC Yeast Culture; YC) in broiler diets on carcass characteristics and humoral immune response. Materials and Methods: A total of 240 one-day-old broiler chicks (Ross 308) were randomly assigned to four YC dietary treatments of 60 birds each. The dietary treatments were 0 (control), 1, 1.25 and 1.5 g YC/kg diet over 42 d. Results and Discussion: The results revealed that the birds fed yeast cultures had statistically increased (P < 0.05) body weight from control birds only at 5-6 weeks of age. The highest inclusion level (1.5g/kg) recorded the best weight. The broiler chicks fed a diet supplemented with 1.25g/kg had the lowest mortality rate over the whole period of the experiment. The birds given the highest level of yeast (1.5g/kg) had significantly (P < 0.05) higher percentage of major and minor breast muscles compared with the others that fed a basal diet. A significantly (P < 0.01) increase in IgM titer was noticed in birds fed diet containing YC levels more than 1g/kg at 7 days post-injection with sheep red blood cells. Likewise, broilers fed a diet containing 1.25g/kg exhibited a higher level of antibody titer against Newcastle disease virus at latter age (on d 42) compared with the other groups. Conclusion: The data suggest improvement in growth performance, carcass yield and humoral immunity of broilers fed yeast culture supplementation diet.


Many other beneficial factors of yeast inclusion such as improved carcass development and breast
In recent years, there has been a great attention to yield were intensively reported.Higher muscle minimize or completely avoid usage of antibiotics in percentage of many parts of carcass was observed both animal and poultry feeding, as well as an [4,9,[17][18][19].On the other hand, some researchers increasing consumer concern for poultry drug residues didn't find an advantage of dietary yeast inclusion on in meat and eggs.In 2006, the European Union carcass measurements [20,21].Use of yeast and yeast imposed a complete ban on the use of antibiotics in products as natural growth promoters and immunoanimal feed as growth promotants.As these bans are modulators is well documented.It may serve as being considered, non-antibiotic alternatives like alternatives to antibiotics for both growth promotion yeast and yeast products are widely used in poultry and disease resistance in poultry production.Several rations to improve growth and productive performance.literature referred that supplementation of yeast Effects of yeast products on production and their mode products improved immune response [2, [22][23][24][25]. of action in poultry have been reported [1].Whole The purpose of the present study was to examine yeast products or yeast cell wall components have the effect of different dietary concentrations of yeast been used to improve growth and affect the culture on growth performance, carcass yield and physiology, morphology, and microbiology of the humoral immunity in broiler chicks.intestinal tract of both broiler chicks [1-9] and turkey
by the Institutional Animal Ethical Committee.

Birds, management, and experimental Design: Antibody response against Sheep red blood cells
A total of 240 one-day-old broiler chicks (Ross 308) (SRBC): Sheep red blood cells (SRBC) were used as were purchased from a commercial supplier.The T-dependent antigens to quantify the antibody chicks were housed in poultry research station at response.At 3 weeks of age, three birds from each Qassim University (Saudi Arabia) and randomly replicate within each treatment were injected assigned to four dietary treatments with similar intramuscularly with SRBC (7% suspension in PBS, 1 average initial weight of 60 birds each.Each treatment ml/bird).Blood samples were collected at 7, 14 and 21 was allotted to 4 caged replicates (each having 15 days after injection.The serum from each sample was chicks).The dietary treatments consisted of the basal harvested and stored at -20°C until tested.Serum was diet supplemented with increasing level of Yeast heat inactivated at 56°C for 30 min and then analyzed Culture (YC); 0 (control), 1, 1.25 (recommended level) for total, mercaptoethanol-sensitive (MES) IgM and and 1.5 g/kg.chicks from each dietary treatment were selected and small amounts (100 g) of the basal diets, then with a slaughtered for carcass evaluation.Birds were larger amount of the diet until the total amount of the individually weighed before slaughter.They were respective diets were homogeneously mixed.No sacrificed by exsanguination and leaved to complete antibiotics were included in the experimental diets of bleeding.Feathers were manually removed after the current study.Environmental conditions were 0 scalding at 60 C for approximate 2 min.The bird was controlled by a computer system according to the standard recommendations for broiler chicks.All processed by removing the head, shanks and feet and birds were kept under the same managerial, eviscerated by removing the viscera.The heart and environmental and hygienic conditions except for liver were dissected from the viscera and the gizzard different dietary levels of yeast.Birds were provided was cut open and rinsed of its contents.Also, bursa of with continuous light.Feed and fresh water were Fabricius and spleen were removed and weighed.The available for ad libitum consumption throughout the carcass was then immersed in cold water.The carcass, 42 d of the experiment.Upon arrival, the temperature thigh, drumstick and breast muscles (minor and major) inside the house was adjusted to 32 C at the first day were weighed.Each portion was expressed as a and was then reduced by 2.5 ºC each week.The mean proportion of the live body weight.value of daily temperature inside the house throughout Statistical analysis: Data were subjected to a onethe whole experimental period was 25±1ºC.
way ANOVA using JMP Ver.8.0.1 [SAS Institute, 28] Growth performance and mortality rate: Body with dietary treatment as a fixed effect.All results are weight in gram was weekly determined until the end of presented as mean and the pooled SEM.The the experiment on individual basis.Mortality was significance of difference among the groups was daily recorded, then mortality rate was calculated over assessed using Duncan's new multiple range test.42 days.
Significance was set as P < 0.05.

Results and Discussion
Broilers were vaccinated with Newcastle disease "La-Body weight and mortality rate: The results of Sota" vaccine (Intervet International B.V., Boxmeer, body weight for each supplemented group are Holland) via drinking water on d 10 and 28.Three presented in Table1.As noticed, body weight of broiler birds from each replicate within each treatment were chicks during earlier ages (through the first four randomly selected and blood was collected from the weeks) didn't significantly improve by the dietary wing vein.The sera were stored at -20ºC until the end inclusion of yeast culture, suggesting that yeast culture of the experiment.Antibody titer against Newcastle didn't play an active role in body weight during the disease virus (NDV) was determined by Haemagginitial stage of growth period.Similarly, Fasina and lutination Inhibition (HI) test on d 28, 35 and 42.The Thanissery [29] observed that the body weight of yeast data were expressed as the logarithm base 2. supplemented group of chicks hatched from young researchers attributed the different response of birds to breeder hens didn't differ from the chicks of the yeast supplementation due to the nature of the unsupplemented group.It should be noted that the experiment conditions.It has been reported that in inclusion of yeast in broiler's ration with 1.25g/kg or order for the yeast products to be effective, the birds 1.5g/kg significantly (P<0.05)improved body weight need to be kept under stress in some way [30].particularly in latter ages (5 and 6 weeks of age) As illustrated in Figure 1.The broiler chicks fed compared with control one.These results confirmed a diet supplemented with recommended level findings described previously by several researchers (1.25g/kg) recorded the lower mortality rate over the [1,9,36,39,40].Furthermore, Chae et al. [37], Moraleswhole period of the experiment.The last observation Lopez et al. [38] and Zhang et al. [25] concluded that is in harmony with the findings of Silva et al., [16] and supplementation of broiler chicken diets with yeast Hosseini [9] who stated that the addition of yeast culture wall or purified fractions has resulted in extract to broiler diets promoted better feed conversion improvements of both body weight gain and feed and better livability at 21 d of age.Similarly, efficiency.On the other hand, Morales-Lopez et al. [7] Tangendjaja and Yoon [31] found that yeast culture evaluated the effect of various yeast cell wall components supplementation reduced mortality in laying hens.on growth performance parameters in broiler chicks, However, studies investigating the mechanisms of but found no effect.Perhaps the components of a yeast yeast action on health and/or immunity are limited.product influence the efficacy of yeast (and yeast-Carcass Characteristics: The effect of feeding containing products) as growth promoters, and, if so, different levels of yeast on dressing carcass, breast, leg each yeast product formulation must be evaluated for and some internal organs percentages are summarized efficacy as a non-antibiotic promoters.
in Table 2.The results showed that the inclusion of Another interesting point noticed from many yeast slightly improved carcass percentage.Also, an previous reports is that the effective inclusion levels increase in thigh percentage was detected for chicks reported for a yeast product are different (0.25% yeast fed a diet supplemented with yeast.Moreover, the culture, Gao et al., [23], 2% Alphamune yeast extract, recommended level recorded the highest percentage.Solis de los Santos et al., [14], 0.075% novel yeast In terms of breast muscles, it could be observed that product, Fasina and Thanissery, [29]).However, many Effect of yeast culture supplementation on carcass yield and humoral immune response of broiler chicks the birds given the highest level of yeast (1.5g/kg) had from 0.04 -0.07%[32].significantly (P<0.05)higher percentage of major and Antibody Response to SRBC: Antibody titer responses minor breast muscles compared with others that fed a have been used as measures of humoral immune status basal diet.Likewise, Hosseini [9] found a significant of birds [33].Total IgG and IgM antibody concenpercentage of carcass, liver, heart and gizzard in trations against SRBC were presented in Table 3.It broilers fed ration containing Saccharomysec could be observed that the birds fed a diet containing Cerevisiaet compared to untreated siblings.Miazzo et YC at the rate of 1g/kg had significantly (P<0.05)al. [18] also reported that the broiler fed yeast (0.3%) higher total antibodies at all tested periods compared had a higher leg muscle than the other group fed a basal with control counterparts.Generally, higher total diet without yeast inclusion.Onifade, [17] found that antibody titer against SRBC in supplemented groups the broiler chicks fed dried yeast had a significantly was noticed.Similarly, Asli et al. [34] and Yalcin et al. greater weight of liver, spleen and gizzard compared to [35] observed greater antibody production against the control siblings.
SRBC in laying hens fed yeast in the diet compared In broilers fed yeast extract (nucleotide source), with the control group.This higher antibody titer in Rutz et al. [4] observed a numerical improvement in laying hens supplemented with yeast autolysate could carcass yield, as well as in drum, thigh, wing and be explained by the beneficial effects of supplemenbreast yields as compared to birds that did not receive tation in maintaining a physiological balance of yeast extract.Similarly, broiler chicks fed a diet immunopotent cells and therefore providing a healthy containing enzymatically hydrolyzed yeast at a rate of environment for the immune system.1% significantly improved yield of the carcass, breast Another interesting point is that the birds fed YC and legs [19].In the other hand, Karaoglu and Durdag, had an increase in IgM titer particularly at 7 days post [20] and Chumpawadee et al. [21] found that yeast inoculation with SRBC.Moreover, the recommended (Sacharomyces cerevisiae) supplementation in level (1.25g/kg) recorded the highest figure at all broiler's diet did not have any effect on hot carcass or tested periods compared to the control group.This cold carcass percentage.There was no effect of result is in agreement with the finding of Gao et al. nucleotides on carcass and parts yields of broilers [23], who found a linearity increased in IgM given a diet containing nucleotides at levels varying associated with increasing level of yeast.This implies

Figure- 1 .
Figure-1.Cumulative mortality rate over 42-day of age The 27]rse powder of yeast culture used mercaptoethanol-resistant IgG anti-SRBC antibodies was obtained from Diamond V Mills, Cedar Rapids, as previously described[26,27].Titers were expressed IA, USA.The birds were fed a corn-soybean meal as the log of the reciprocal of the highest dilution

Table 1 .
Effect of supplemental yeast culture in broiler diets on live body weight in g a-c Means within a row within titer with no common superscript differ significantly.

Table 2 .
Effect of supplemental yeast culture in diet on carcass characteristics of 42-day-old broilers a-c Means within a row within titer with no common superscript differ significantly.

Table - 3
. Antibody responses against SRBC expressed as total antibody titres, mercaptoethanolresistant titres (IgG) and mercaptoethanol-sensitive titres (IgM) concentrations in different supplemented groups.abc Means within a column within titer with no common superscript differ significantly.PI = post SRBC-injection that YC may stimulate the humoral immune system to Competing interest produce more antibodies.Increased antibodies cover Authors declares that they have no competing interest.the surface of intestinal mucosa and can protect villi from damage.It was proposed that oligosaccharides in References the yeast cell wall could bind to viruses and work as 1.Mansour, S., Al-Khalf, A., Al-Homidan, I., Fathi, M.M. (2011) Feed efficiency and blood hematology of Author's contribution broiler chicks given a diet supplemented with yeast Moataz Fathi and Sultan Al-Mansour participated in culture, Int.J. Poult.Sci.10: 603-607.the preparation of the experimental design.Moataz 9. Hosseini, S. (2011) The effect of utilization of different levels of Saccharomysec cerevisiae on Fathi analysed data, sample and wrote the final draft of broiler chicken's performance.Global Vet.6: 233the manuscript.All the authors has read and approved [23], G.R., Huff, W.E., Rath, N.C., Tellez, G. (2006) Limited treatment with β-1,3/1,6-glucan improves inoculation (on d 42) compared with the other production values of broiler chickens challenged with supplemental levels.That is meant the birds given Escherichia coli.Poult.Sci.85:613-618.recommendedlevelhasa good immune memory cells 4. Rutz, F., Anciuti, M.A., Rech, J.L., Gonçalves, F.M., to reconstitute the same antibodies after inoculation Delgado, A.D., Rosa, E.R., Zauk, N., Ribeiro, C.L.G., with boost antigen.Gao et al.[23]found that antibody

Table - 4
. Total anti-NDV antibody titer of commercial broiler strains as affected by yeast supplementation Effect of yeast culture supplementation on carcass yield and humoral immune response of broiler chicks