مجله تولیدات دامی
سال بیست و سوم شماره 3 (پاییز 1400)

Monitoring the inbreeding rate of native chickens in breeding stations is of significant importance because of planned matings and lack of gene flow inthe population. This study was undertaken to estimate the inbreeding coefficient, investigate the trend of inbreeding changes and evaluate the effects ofinbreeding depression on the economic traits in Isfahan improved native chicken population. The studied traits were body weight, age at sexualmaturity, weight at sexual maturity, egg number, mean egg weight and egg weight at first day. In the present study, data of 97272 birds recordedduring 21 generations were included. In order to estimate the inbreeding coefficient of each bird and the effect of inbreeding on the traits, CFC andWOMBAT software were used, respectively. Pedigree analysis indicated that 79.48 percent of population were inbred. The estimated averageindividual and maternal inbreeding coefficients were 4.3 and 3.5 percent, respectively. According to results, for every one percent increase ininbreeding, rate of inbreeding depression for the traits including the body weight in 1 day, 8 weeks and 12 weeks, age at sexual maturity, weight atsexual maturity, egg number, average weight of eggs and egg weight at first day was -0.008, -2.52, -3.51, 0.23, -3/97, -0.13, 0/02 and 0.06,respectively. Based on the results of the present study, although in closed populations under genetic selection, the absence of inbred bird is almostimpossible, but, the reduction of inbreeding can be achieved by controlling the matings, which prevents the adverse effects of inbreeding in thepopulation.

The aim of this study was to evaluate the effect of crossbreeding on growth performance and carcass composition of purebred and crossbred Kurdilambs. Thus, two genetic groups including purebred Kurdi lambs (KK) and crossbred Kurdi*Romanov lambs (KR) were used. For analysis of carcasstraits, six lambs from each group were selected and slaughtered. The number of weaned lambs for KK and KR were 95 and 45, respectively. Ourresults indicated thatKK purebred lambs had the highest (4.5 kg) and KR crossbred lambs had the lowest (4.1 kg) birth weight (P < 0.05). CrossbredKurdi*Romanov lambs had higher average daily gain than KK purebred lambs (P < 0.05). The means of final weights of purebred lambs weresignificantly higher than crossbred lambs (54.8 vs. 41.5 kg, respectively). The genetic groups had no significant effect on cold and hot carcass weights.The effect of crossbreeding on fat thickness, fat-tail and leg was significant (P < 0.05). Crossbred lambs performed better than purebred lambs in thepre-weaning period, but purebred Kurdi lambs performed better than crossbred lambs in the fattening period. In general, it can be reported that thecrossbreeding of Kurdi sheep with Romanov sheep did not show the desireble results.

This study was conducted to compare the effect of a cellulosic (wheat straw; WS) and non-cellulosic (beet pulp; BP) forage source on high producingdairy cows during the transition period (three weeks before to six weeks after calving). Multiparous Holstein cows (n=36) with mean body weight of697±59.6 kg and body condition score of 3.3±0.22 were used in the experiment. Before calving, the cows received diets containing 7.17% WS (n=18)or BP (n=18). After calving, the cows in each group were divided into two subgroups (n=9), and received the diets containing 5% BP or WS.Prepartum dry matter intake (DMI) was similar between dietary treatments but prepartum digestibility of DM (P=0.05) and neutral detergent fiber (P=0.06) was lower in cows feeding on the WS diet. The yield of energy-corrected milk, 4% fat-corrected milk and milk fat percentage tended to behigher in the cows fed with the BP diet during the prepartum period (P = 0.09). In conclusion, the results showed that feeding non-cellulosic foragesduring the transition period may improve the performance in dairy cows.

In order to investigate the effect of using different levels of pistachio seed coat (PSC) on feed intake, ruminal parameters, microbial protein synthesis and nitrogen retention in Kermani sheep, four male sheep with a mean weight of 54 ± 2 kg were used. This experiment was conducted in 4×4 Latin square design in four periods of 21 days. After determining the chemical composition of PSC, it was used in the preparation of experimental diets and replaced with wheat bran. The experimental diets were: 1) control diet (without PSC), 2) diet containing 5 % PSC, 3) diet containing 10 % PSC and 4) diet containing 15 % PSC. The results showed that feed and nitrogen intake, excreted nitrogen and nitrogen retention were not affected by feeding the experimental diets. Adding PSC to the diet, ruminal ammonia nitrogen was reduced (P<0.05), however, it did not affect the pH of ruminal fluid at 0, 2, 4, 6 and 8 hours after feeding (P<0.05). The total protozoa population of the rumen was not affected by experimental diets, while the population of cellulolytic species increased linearly (P<0.05). Among sheep, no significant difference was observed in terms of total purine derivatives, allantoin, creatinine, uric acid, hypoxanthine and xanthine and, of course, microbial protein synthesis. According to the results, and no difference in the factors between the control group and other experimental groups, it can be said that PSC can be used up to 15% of dry matter in sheep diet and can be replaced with wheat bran or other diet ingredients.

The objective of this study was to investigate the effect of decreasing dietary protein content with supplementing protected methionine (pMet) andlysine (pLys) on intake, milk yield, metabolic status, and apparent digestibility of nutrients in Holstein fresh cows. Immediately after calving, 16 cowswith the similar BCS and parity were randomly assigned to two treatments. Experimental diets provided equal amounts of lysine (132 to 133 g/d) andmethionine (40 to 43 g/d). The treatments were: a diet containing 18.35 % CP without supplementing pMet and pLys (HP); and a diet containing16.45 % CP with supplementing rumen-protected amino acids (LPML). Individual dry matter intake and milk yield were recorded daily during freshperiod. Blood samples were collected at 0, 3, 7, 14 and 21 d after calving to determine the serum concentrations of mineral and metabolites. Feedintake was not affected by experimental diets but milk yield was higher for HP cows than cows in LPML (P < 0.01). The yield of milk protein,lactose, fat and concentration of milk urea nitrogen (MUN) were higher in HP cows compared to LPML (P < 0.05). Compared to HP cows, cows inLPML had lower blood urea nitrogen (BUN) and higher serum concentrations of total protein and globulin (P < 0.01). Based on the results of thepresent study, reducing dietary protein content while maintaining the supply of limiting amino acids decreased lactational performance and feedefficiency of Holstein fresh cows.

The current study was conducted to investigate the effect of dietary supplementing of condensed molasses soluble (Vinasse) in heat stressed midlactatingHolstein cows on milk yield and composition, apparent nutrient digestibility and economical parameters. The experiment was performed by84 Holstein lactating dairy cows (DIM: 155±25; MY: 32±3) in a completely randomized design with three treatments 1) basal diet without vinous(control), 2) diet containing 5% of vinasse (2.2 kg/head/day) and 3) diet containing 10% 0f vinasse (4.4 kg/head/day). The study was conducted in thesummer season with a temperature -humidity index of 75.1. The experiment lasted for 25 days (15 days for adaptation and 10 days for sampling). Drymatter intake of the treatment fed a 10% vinasse supplemented diet was higher than the other treatments (P<0.05). Dry matter and NDF digestibilitycoefficients were increased by increasing the level of vinasse in the diets, compared to the control (P<0.05). The economical index of income overfeed cost was the highest for the diet containing 5% of vinasse. Totally, regarding to the chemical composition of the vinasse and its beneficial impactson the performance of the cows under heat stress, using 5% of dry matter vinasse supplementation (2.2 kg wet weight/day or 1.1 kg dry matter/day)can improve nutrient digestibility and reduce feed costs without any adverse effects on dry matter intake.

The aim of this study was to investigate the effect of Lactobacillus fermentum 92069 (LF) isolated from yogurt on chemical and microbialfermentation and aerobic stability of high moisture corn silage. After propagation and concentration determination LF was used to prepareexperimental treatments with concentrations of zero (control, LF0), 1×106 cfu/g fresh forage (LF1) and 2×106 cfu/g fresh forage (LF2). Three replicatesof each treatment were stored in laboratory silos for 90 days. The results showed that the chemical composition of silages (DM, NDF, ADF, CP,WSC) was not affected by addition of LF. LF2 had a significant lower pH compared to the control (P<0.05). LF1 and LF2 silages showed a higherconcentration of lactic acid (P<0.05). Concentration of acetic acid increased and mold population decreased in LF2 compared to the other silages(P<0.05). There was no significant difference between population of lactic acid bacteria and yeast in silages. The aerobic stability of LF0 and LF1silages decreased significantly compared to LF2 (P<0.05). During the aerobic stage after opening the silos, LF2 silage had the lowest pH (P<0.05).However, yeast population of silages during the aerobic stage was not affected by treatment. The results of this study showed that Lactobacillusfermentum 92069 has the potential to be used as a silage inoculant.

The effect of garden thyme essential oil (TEO) and rapeseed oil (RO) on performance, immune traits and intestinal morphology using 432 one-dayoldRoss 308 male broiler as a (3x3) factorial experiment in a completely randomized design including different levels of TEO (0, 300 and 500 ppm)and RO (1, 3 and 5 percentage) were evaluated with 9 treatments and 4 replicates. Throughout the rearing period, broiler chickens receiving 3%gained more weight than 1% of RO and chickens receiving 300 ppm gained more weight than those without TEO (P˂0.05). The use of 3% RO + 300ppm TEO increased the thigh percentage compared to 1% RO. At 1 and 5 percentage levels of RO, with increasing levels of TEO in the diet, bloodcholesterol and LDL concentrations decreased and blood HDL increased (P<0.01). Levels of 3% and 5% of RO + 300 and 500 ppm of TEO in broilerchicken diets increased lymphocyte percentage and antibody titer against Newcastle disease and decreased heterophil percentage and heterophil tolymphocyte ratio of blood (P<0.05). Broiler chickens receiving diet containing TEO had the highest ratio of villi height to crypt depth (P<0.01). Basedon the results, the level of 3% rapeseed oil + 300 ppm thyme essential oil in the diet of broiler chickens can be used to improve performance,immunity and biochemical traits of blood.

This study was conducted to investigate the effects of toxin binders and prebiotics on growth performance, intestinal microbial population, stress andantioxidant indexes of broiler chicks fed diets contaminated with aflatoxin B1. In this study, 600 1-d-old mixed broiler chicks (Ross 308) wereinvestigated in 10 treatments with 6 replications and 10 chicks per replication. Experimental treatments included: Negative controls un-supplementedand supplemented with ASRI1 and ASRI2 toxin binders and prebiotic and positive groups un-supplemented and supplemented with ASRI1 andASRI2 toxin binders and prebiotic, ASRI1 +prebiotic and ASRI2 +prebiotic. Growth performance, stress indexes of heterophile, lymphocyte,bacterial population and stress indexes of super oxide dismutase (SOD), glutathione peroxidase (GPx) and malondialdehyde (MDA) wereinvestigated. Dietary inclusion of aflatoxin into diet increased heterophile, heterophile:lymphocyte ratio and decreased lymphocyte (P<0.05), but toxinbinders and prebiotic alleviated effects of aflatoxin on heterophile and lymphpocyte. Thepopulation of E. coli and lactobacilli were significantlyhigher and lower in positive control compared to negative control (P < 0.05). The results also showed that the serum concentrations of antioxidantenzymes were significantly lower in negative control compared to positive control (P < 0.05). In sum, aflatoxin showed negative effects on growthperformance, intestinal microbial populations, stress and antioxidant indexes but toxin binders and prebiotic decreased its negative effects andinclusion of ASRI1(3kg/ton) was better than other toxin binders.

The current study aimed to investigate the effects of adding probiotic and encapsulated thyme essential oil (TEO) on growth performance and immuneresponses of broiler chicks by multi attribute decision making (MADM). In the current study, 420 broiler chicks were allocated into 7 experimentalgroups with 6 replication and 10 broiler chicks per replication for 42 days. The experimental treatments were included 1) diet lack of TEO andprobiotic (control), 2) diet containing 100 mg probiotic, 3) diet containing 100 mg TEO, 4) diet containing 200 mg probiotic, 5) diet containing 200mg TEO, 6) diet containing 100 mg probiotic+100 mg TEO, and 7) diet containing 200 mg TEO+ 200 mg probiotic. Growth performance andhumoral immune responses were investigated. Index weights for weight gain, feed conversion ratio, production index were 0.2, 0.15 and 0.25,respectively and index weight of 0.1 was considered for other parameters. Coefficients for control, probiotic 100, TEO 100, probiotic 200, TEO 200,probiotic 100 + TEO 100 and probiotic 200 + TEO 200 were 0.0476, 0.126, 0.198, 0.315, 0.427, 0.727 and 0.956, respectively. Thus, adding 100 mgprobiotic and 100 mg TEO into diet increased immune response and growth performance. Based on obtained results, it is suggested that dietaryinclusion of 100 mg TEO + 100 mg probiotic in diet of broiler chicks has a potential to improve immune response and growth performance.

A 42-d study was conducted to investigate the effects of emulsifier and inulin supplementation in diets with different sources of fat on growthperformance, carcass traits, immune response, and blood biochemical indices of broilers. A total of 800 one-day-old male broilers in a 2 × 2 × 2factorial experiment with two fat sources (soybean oil and beef tallow), two emulsifier levels (0 and 0.1% lysophospholipids) and two levels of inulinsupplementation (0 and 0.1%) were used in a completely randomized design with eight treatments, five replications and 20 chicks per replicate. Birdsfed diets containing beef tallow and emulsifier had a lower feed conversion ratio and abdominal fat percentage than birds fed diets containing soybeanoil and emulsifier (P <0.05). The abdominal fat percentage and feed conversion ratio were lower in birds that received fat and inulin diets than otherbirds (P<0.05). Birds fed the emulsifier-containing diet had higher values of primary and secondary antibody titers against Newcastle disease virus,and secondary titers of total antibody and IgM against sheep red blood cells (SRBC) compared to those fed the emulsifier-unsupplemented diet(P<0.05). Daily weight gain and antibody titer against Newcastle disease and SRBC were higher in birds receiving the inulin-supplemented dietcompared to other birds (P<0.05). In conclusion, the use of 0.1 % emulsifier and inulin, either singly or in combination, in the diet of broiler chickenscan be useful for improving growth performance and immune response.

In this research the effect of using domestic (Multibehcil) and imported (Bioplus B2) probiotic supplements and Avilamycin antibiotics wereinvestigated on performance, parameters of blood lipid and small intestine morphology by a sample of 360 male Ross-308 broilers aging 11 to 42days-old in a completely randomized design with 6 treatments, 4 replications and 15 chickens per each replicate. Experimental treatments included 1)without additive (control), 2) diets containing 0.1% of commercial bioplus B2 probiotic, 3) diets containing 0.01% of avilamycin antibiotic andtreatments 4) to 6) diets containing 0.05%, 1% and 0.15% of Multibehcil, respectively. The results showed that body weight and feed conversion ratiowas improved by using bioplus B2 probiotic and antibiotic (P < 0.05). Body weight and feed conversion ratio in birds receiving 0.1% and 0.15% ofMultibehcil were not significantly different from birds receiving bioplus probiotic. Feed intake was not affected by the experimental treatments.Humoral immune response and intestinal morphological parameters in birds receiving 0.15% of Multibehcil was not significantly different from thecontrol group and it was statistically equal to the groups receiving bioplus probiotics and antibiotics. The LDL level of blood showed a significantdecrease in Bioplus B2, antibiotic and 0.15% of Multibehcil treatments (P < 0.05). In general, the results indicated that using of Multibehcil at thelevel of 0.15 percent can be a suitable alternative for both Bioplus B2 and Avilamycin during grower and finisher period in broilers.

In order to investigate the applicability of using male Leghorn chicken powder for laying hens, the experiment was performed with two hundred 50weeks old Bovans laying hens during three periods of 28 days in a completely randomized design, with 5 treatments, 5 replications, and 8 laying henper each replication. The dietary treatments were 0, 4, 8, 12, and 16 percent chicken powder. The results showed that during the whole of the rearingperiod, egg weight was increased when the hens were fed with 4 percent chicken powder, in comparison to 8 and 16 percent levels (P < 0.05). Withincreasing the level of chicken powder in the diet from 12 to 16 percent, feed intake significantly decreased during 50-53 weeks period and wholerearing period (P < 0.05). Dietary treatments had no significant effect on feed conversion ratio, hen-day egg production, egg mass and egg shellthickness. The highest yolk color index was observed in hens fed with 12 and 16 percent chicken powder in comparison to the control and 4 percenttreatments (P < 0.05). Consumption of 16 percent chicken powder increased shell resistance in comparison to the control (P < 0.05). Using chickenpowder, up to 12 percent level, significantly decreased feed cost to produce one Kg egg. In conclusion, chicken powder up to 12 percent level does notseem to have an adverse effect on laying hens performance, but further researches are needed to evaluate the effects of chicken powder at 16 percentlevel.

This study aimed to investigate the effect of malt extract on growth performance, nutrient digestibility, and cecum microbial population of broilers ingrower, finisher, and whole periods. For this experiment, 256 pieces of mixed female and male day-old Cobb 500 broiler chicks were used in acompletely randomized design with 4 treatments, 8 replications, and 8 birds per replicate from 14 to 49 days of age. Experimental treatments includeda basal diet without additive (control) and a basal diet containing levels of 0.1, 0.2, and 0.3 percent malt extract. The effect of treatments on growthperformance, intestinal length and weight, nutrient digestibility, and the number of Escherichia coli and Lactobacillus in cecum were measured. Theresults showed that in grower, finisher, and whole periods, the addition of malt extract at the level of 0.3 percent, without affecting feed intake,produced the highest daily weight gain and lowest feed conversion ratio compared to other treatments (P≤0.05). Also, the diet containing 0.3 percentof malt extract improved the digestibility of dry matter, protein, and fat and decreased the number of Escherichia coli in the cecum (P≤0.05).According to the results, 0.3 percent malt extract can be used in the diet of broilers to improve the performance and health of gastrointestinal tract.