Evaluation of chopped switchgrass and chopped bermudagrass as litter materials over multiple heavy broiler flocks

Chopped switchgrass (SG) and chopped bermudagrass (BG) were evaluated as alternatives to pine shavings (PS) for broiler litter over 3 flocks. Twenty-four pens were filled with the 3 litter types. Live performance parameters included mortality, BW, BW gain, feed consumption, and feed conversion. Mortality was not different for litter type or flock. All other live variables were different (P < 0.0001) for flock. Mean foot pad scores (FPS) were only different (P < 0.0001) for flock. Litter performance variables included litter and cake moisture content (MC), pH, litter ammonia concentration, and cake nutrient values [nitrogen, phosphorus, and potassium (N–P–K)]. Litter and cake MC differed by litter type and flock (P < 0.0001). Litter MC was 1% lower for SG than BG or PS. Cake depth observations were similar for litter type. Litter pH differed by flock (P = 0.008) while cake pH differed for both litter type (P = 0.05) and flock (P < 0.0001). Beginning and ending litter ammonia concentration were different for flock (P < 0.0001). Potassium was different for both litter type (P = 0.04) and flock (P < 0.0001) while nitrogen and phosphorus differed only by flock (P < 0.0001). Chopped SG and BG performed as well as PS as a litter material over 3 grow-out cycles. Based on the results of this study, chopped grass materials appear to be a viable alternative to PS for broiler bedding.     

Effect of herbal feed additives on performance parameters,intestinal microbiota,intestinal morphology and meat lipid oxidation of broiler chickens

ABSTRACT

1. This feeding trial investigated the effects of herbal feed additives on performance of broiler chickens, jejunal and caecal microbiota, jejunal morphology, meat chemical composition and oxidative stability during refrigerated storage.

2. In a 42 days trial, 320 one-day-old broiler chickens were randomly allocated to 4 groups with 4 replicate pens each containing 20 chicks. The control group was fed maize–soybean-based diets. The diets of the other three groups were supplemented with herbal feed additives: HRB1 with Stresomix^TM (0.5 g/kg feed); HRB2 with Ayucee^TM (1.0 g/kg feed); HRB3 with Salcochek Pro^TM (1.0 g/kg feed). The GC/MS analysis of the feed additives showed that the major components of HRB1 were β-caryophyllene (14.4%) and menthol (9.8%); HRB2 were n-hexadecanoic acid (14.22%) and β-caryophyllene (14.4%); and HRB3 were menthol (69.6%) and clavicol methyl ether (13.9%).

3. Intestinal samples were taken at 42 day to determine bacterial populations (total aerobe counts, Lactobacilli, and Escherichia coli) and perform gut morphology analysis. Meat samples were analysed for chemical composition and oxidative stability under storage.

4. The HRB1 group had improved (P < 0.05) body weight gain and tended to have improved (0.05 ≤ P < 0.10) feed conversion ratio, compared to the control group. Jejunum lactic acid bacteria counts were increased (P < 0.001) in groups HRB1 and HRB3, compared to the control group, whereas caecal lactic acid bacteria counts tended to increase (0.05 ≤ P < 0.10) in group HRB1, compared to the control group. Breast meat fat content tended to be lower (0.05 ≤ P < 0.10) in group HRB1. Meat oxidative stability was improved (P < 0.001), and jejunum villus height, crypt depth and goblet cells numbers were increased (P < 0.001) in all three herbal supplemented groups, compared to the control.

5. In conclusion, herbal feed additives may be able to improve both growth performance and antioxidant activity of broiler chickens, based on their phenolic compound content.     

Gaseous emissions,growth performance and pork quality of pigs housed in deep‐litter system compared to concrete‐floor system

This study measured gaseous emissions, growth performance and pork quality in a deep‐litter system and concrete‐floor system. Three hundred and twenty weaned piglets with an average body weight (BW) of 6.0 ± 0.3 kg were assigned randomly into three treatments. Treatments 1 and 2 included four pens with 20 pigs for each pen respectively in the deep‐litter system, and the ratio of sawdust to chaff was 5:5 and 3:7 for treatments 1 and 2 respectively, the probiotics inoculated into the fermentation bedding for both treatments were composed of Saccharomycetes, Bacillus subtilis and Actinomycetes; treatment 3 was the conventional concrete‐floor system including eight pens with 20 pigs for each pen. The concentration of NH₃ and CO₂ in the deep‐litter system was significantly (P < 0.001) lower than that in the concrete‐floor system. The ratio of feed to gain for pigs raised in the deep‐litter system was significantly (P < 0.05) lower than that for pigs housed in the concrete‐floor system. The carcass weight and length, color score and rate of cooking meat for pork from the deep‐litter system were significantly (P < 0.05) higher than those from the concrete‐floor system. Results indicate that pigs raised in the deep‐litter system had some animal welfare improvements and an odor nuisance reduction; in the meantime, pork quality also improved from the deep‐litter system compared to the pigs housed in the concrete‐floor system.     

Effects of supplementing Barodon,Bacillus subtilis,and Ampbio on growth performance,biochemical metabolites,and hormone levels in Korean native heifers

An experiment was conducted to evaluate the effects of supplementing feed additives of Barodon®, effective microorganism® (Bacillus (B.) subtilis), and Ampbio® on the growth performance, blood metabolites, stress, and reproductive hormone levels of Korean native heifers. A total of 48 Korean native heifers were assigned to four groups with 6 heifers in each group. The groups were control, Barodon (0.2%), beneficial microorganism (1%), and Ampbio (1%). Animals in all groups were fed a basal diet composed of selected feed additives and water ad libitum for 99 days. Results showed that there are significant changes in body weight and daily gain in the Ampbio-supplemented group as compared with the control and other feed additives groups (p?<?0.05). The increased level of feed intake (7.30?±?0.03 kg) and feed requirements (10.81?±?0.52 kg) was observed in the Ampbio-fed group followed by the effective microorganism (EM), Barodon, and control groups. There were no significant changes in albumin, glucose, glutamic oxaloacetic transaminase (SGOT), serum pyruvic transaminase (SGPT), and total protein level, but the decreased levels of total cholesterol and triglycerides and the increased level of blood urea nitrogen were noted in the Ampbio-fed group as compared with the control and other feed additive groups. The reduced level of cortisol (p?<?0.05) and elevated levels of progesterone and estradiol (p?>?0.05) were noted in the Ampbio-fed group as compared to the other feed additive groups. It is therefore concluded that incorporation of Barodon, EM (B. subtilis), and Ampbio in the recommended diet improved the growth and health performance of Korean native heifers.

     

Fermentation quality and chemical composition of shrub silage treated with lactic acid bacteria inoculants and cellulase additives

Effects of lactic acid bacteria (LAB) inoculants and cellulase additives on fermentation quality and chemical compositions of shrub silages were studied by using a small‐scale fermentation system. Two LAB inoculants of Qingbao (Lactobacillus plantarum, Pediococcus acidilacticii, Lactobacillus casei and Clostridium phage) and Caihe (Lactobacillus plantarum, Lactobacillus brevis and Pediococcus acidilactici) and a commercial cellulase made from Trichoderma reesei were used as additives for intermediate pea‐shrub, rush bushclover, arborescent ceratoides and shrubby silage preparation. The crude protein, neutral detergent fiber and water‐soluble carbohydrate contents of the four shrub materials were 10.1–14.2, 62.6–67.2 and 1.9–3.5% on a dry matter basis, respectively. All shrub silages had pH 3.40–4.43, ammonia‐N 0.1–0.2% g/kg and lactic acid 1.3–2.9% on a fresh matter basis. The silage quality of LAB‐inoculated silages did not have a greater effect than control silages, except shrubby silage preparation. Silages treated with the cellulase, the pH of rush bushclover and shrubby sweetvetch silage were significantly (P < 0.05) lower and the lactic acid content were significantly (P < 0.05) higher than the control silages. The results confirmed that shrub contained a relatively high content of crude protein; its silages can be preserved in good quality, and they are new potential resources for livestock feed.     

Effects of Armillariella tabescens mycelia on the growth performance and intestinal immune response and microflora of early‐weaned pigs

This study was performed to evaluate effects of Armillariella tabescens (A. tabescens) on the growth performance and intestinal immune response and microflora in early‐weaned pigs when used as feed additive. A. tabescens mycelia were added to basal diets at concentrations of 0%, 0.1%, 0.3% or 0.9% (w/w). A total of 144 commercial cross‐bred piglets were randomly allocated to one of these four diets and fed for 30 days. The growth performance of early‐weaned piglets displayed improvement with diets containing 0.1% and 0.3% dried mycelia powder from A. tabescens. Supplementing with 0.1% or 0.3% A. tabescens mycelia induced a 2.6‐ and three‐fold increase in secretory immunoglobulin A (sIgA) content in the jejunal mucosa, respectively, but had only a marginal effect on sIgA in the ileal mucosa. Expression of interleukin‐2, interferon‐γ, and tumor necrosis factor‐α in the jejunal mucosa were elevated with A. tabescens mycelia administration. Increased amounts of Lactobacillus spp. and Bifidobacterium spp. in the jejunum, and decreased amounts of Escherichia coli in the jejunum and ileum were observed with the administration of A. tabescens‐containing diets. This study demonstrated that A. tabescens had beneficial effects on the growth performance and intestinal microflora of early‐weaned pigs.     

Supplementation of protease,alone and in combination with fructooligosaccharide to low protein diet for finishing pigs

Effects of adding protease with or without fructooligosaccharide (FOS) to low protein diet on growth performance, nutrient digestibility and fecal noxious gas emission were evaluated in 160 finishing pigs (57.70 ± 1.16 kg) in a 9‐week study. Pigs were randomly divided into four dietary treatments, PC: positive control diet (15.97% crude protein (CP)); NC: negative control diet (12.94% CP); PRO: NC supplemented with 0.05% protease; PROFOS: NC supplemented with 0.05% protease and 0.1% FOS. During weeks 4–9 and weeks 0–9, gain : feed ratio was impaired (P < 0.05) in pigs fed NC diet compared with those fed PC, PRO and PROFOS diets. Pigs fed PC, PRO and PROFOS diets had higher (P < 0.05) apparent total tract digestibility (ATTD) of CP than pigs fed NC diet. Pigs fed PROFOS diet had reduced (P < 0.05) ammonia emissions compared to pigs fed NC and PRO diets. These data indicate that reducing dietary CP concentrations impaired growth performance, decreased ATTD of CP and reduced ammonia emissions. Supplementation of protease in low CP diet improved growth performance and increased ATTD of CP. Dietary supplementation with protease and FOS in low CP diet improved growth performance, increased ATTD of CP and decreased fecal ammonia emission.     

The effect of litter materials on broiler performance: a systematic review and meta-analysis

ABSTRACT

1. Divergence in outcomes from studies on the effects of litter materials on body weight, feed intake, feed conversion and mortality in broilers has led to a need for a meta-analysis to quantify their effects.

2. A systematic search of published quantitative research relating to wood shavings and alternative bedding litters was conducted using databases.

3. Means, standard deviations and sample sizes were extracted from each study. The response variables were analysed using the standardised mean difference (SMD, control treatment minus alternative litters).

4. The literature demonstrated that alternative materials have no impact on feed intake in broilers, compared to wood shavings (SMD = 0.064, 95% CI = ?0.101–0.229, P = 0.44).

5. There was a positive overall effect of wood shavings on body weight (SMD = 0.253, 95% CI = 0.073–0.433, P = 0.006), feed conversion (SMD = ?0.169, 95% CI = ?0.327 – ?0.012, P = 0.03) and mortality (SMD = ?1.069, 95% CI = ?1.983 – ?0.155, P = 0.02) of broilers, compared to other litter types.

6. Subgroup meta-analysis revealed that straw, when used as an alternative litter material to wood shavings, may be responsible for lower body weight (SMD = 0.654, 95% CI = 0.162–1.146, P = 0.009), worse feed conversion (SMD = ?0.487, 95% CI = ?0.828 – ?0.145, P = 0.005) and higher mortality rates of broilers (SMD = ?3.25, 95% CI = ?5.681 – ?0.819, P = 0.009). Rice husks impaired body weight compared to wood shavings (SMD = 0.535, 95% CI = 0.065–1.004, P = 0.02).

7. It was concluded that different litter types do not affect the broilers’ feed intake. Conversely, broilers kept on straw showed lower body weights, worse feed conversion and higher mortality rates, in comparison to wood shavings. Rice husks decreased body weight compared to wood shavings.     

Natural zeolites in diet or litter of broilers

1. This study aims to analyse the influence of adding natural zeolites (clinoptilolite) to the diet or litter of broilers and their effects on growth performance, carcass yield and litter quality.

2. Three consecutive flocks of broilers were raised on the same sawdust litter, from d 1 to d 42 of age, and distributed in three treatments (control with no added zeolites, addition of 5 g/kg zeolite to diet and addition of 100 g/kg zeolites to litter).

3. The addition of zeolites to the diet or litter did not affect growth performance or carcass yield.

4. The addition of zeolites to the diet did not influence moisture content of the litter, ammonia volatilisation was reduced only in the first flock and pH of litter was reduced in the second and third flock.

5. However, the addition of zeolites to the litter reduced moisture content, litter pH and ammonia volatilisation in all flocks analysed.

6. The addition of 5 g/kg zeolite to the diet in three consecutive flocks was not effective in maintaining litter quality, whereas the addition of 100 g/kg natural zeolites to sawdust litter reduced litter moisture and ammonia volatilisation in three consecutive flocks raised on the same litter.

     

Herbal plants and their derivatives as growth and health promoters in animal nutrition

The purpose of this review is to summarize the effectiveness, modes of action and commercial application of herbal plants and their derivatives as growth promoters for animal. Feed supplements are a group of feed ingredients that can cause a desired animal response in a non-nutrient role such as pH shift, growth, or metabolic modifier (Hutjens, 1991). Common feed additives used in animal diets include immunostimulators, antimicrobials, antioxidants, pH control agents and enzymes. Herbal plants, are a new class of growth promoters and in recent years this feed additives have gained extensive attention in the feed industry. They are a wide variety of herbs, spices, and products derived thereof, and are mainly essential oils. Although numerous reports have demonstrated antioxidative and antimicrobial and immune stimulation efficacy in vitro, respective experimental in vivo evidence is still quite limited. A limited number of experimental comparisons of herbal plants feed additives with antibiotics or organic acid have suggested similar effects on the animal gut microflora. Gut microflora has significant effects on host nutrition, health, and growth performance by interacting with nutrient utilization and the development of gut system of the host. In addition, some phytogenic compounds seem to promote intestinal mucus production. However, the future of using herbs in animal feeding will in great measure depend on the knowledge of chemical structure, their value and characteristics of practical herbs or their extract physiological needs and well-being of animal, and, above all on consumer’s preferences and expectations.     

Evaluation of three different patterns of feed intake during early lactation in lactating sows

Forty‐five multiparous sows (Landrace × Yorkshire; parity: 3.58 ± 1.30) were used to determine the effects of three patterns of feed intake during early lactation on the performance of lactating sows. Experimental treatments were as follows: IFI‐1.4, the amount of feed increased by 1.4 kg per day for the first 5 days post‐farrowing, followed by ad libitum feeding until weaning; IFI‐1.0, the amount of feed increased by 1.0 kg per day for the first 7 days post‐farrowing, followed by ad libitum feeding until weaning; IFI‐0.7, the amount of feed increased by 0.7 kg per day for the first 10 days post‐farrowing, followed by ad libitum feeding until weaning. The number of live piglets at birth/litter in three dietary treatments was 11.50, 10.07, and 10.85, respectively. Sows in the IFI‐1.4 treatment had lower backfat loss during lactation, greater daily feed intake during days 1–6, 7–12, and 1–24 compared with those in the IFI‐0.7 treatment (p < .05). The litter weaning weight, litter weight gain, and average litter daily gain in the IFI‐1.4 treatment were greater compared with those in the IFI‐0.7 treatment (p < .05). In conclusion, the results indicated that the IFI‐1.4 feed intake pattern allowed lactating sows and their litters to obtain optimal performance.     

Poultry litter ash as a replacement for dicalcium phosphate in broiler diets

An experiment was designed to evaluate the nutritional value of poultry litter ash (PLA) under commercial-type conditions. Diets were formulated to meet the nutrient requirements of the broiler utilizing PLA at combinations of 0, 25, 50, 75, or 100% in starter, grower, and finisher diets as a replacement for dicalcium phosphate (DP). No significant effects were observed on BW, feed consumption, FCR, or mortality when broilers were fed PLA to 100% replacement for DP to 41 d of age. Processing performance, as measured by carcass and meat yield, of broilers at 42 d of age was also unaffected (P > 0.05). The complete substitution of DP with PLA failed to compromise growth and processing performance in market age broilers and the PLA produced via the combustion of poultry litter can be used as a phosphorus source in poultry diets.     

The effect of fermented persimmon shell diet supplementation on the growth performance and blood parameters in finishing pigs

The objective of the present study was to investigate the effects of fermented persimmon shell diet (FPSD) supplementation on growth performance and blood parameters in 96 Berkshire pigs. The FPSD was made from persimmon shell and mixed with rice bran and barley bran. Samples of FPSD on day 0 (D0) and day 60 (D60) were analyzed for chemical composition, pH and organic acids. The experimental diets were 0, 3, 5 and 7% FPSD added to C, T1, T2 and T3 of finishing diets on fresh matter basis. Dry matter (DM) was lower (P < 0.01) and crude protein was higher (P < 0.01) on D60 than on D0. pH value decreased (P < 0.01) on D60 than on D0 but organic acids were increased (P < 0.01). Average daily gain was higher (P < 0.05) in T2 than in other groups. Average daily feed intake was higher (P < 0.05) in T2 than in other groups. Total cholesterol was higher (P < 0.05) in T3 than in other groups. High‐density lipoprotein cholesterol increased (P < 0.05) in groups by the addition of FPSD. Blood urea nitrogen was lower (P < 0.05) in C than in other groups. The results indicate that FPSD improved the growth performance and blood parameters in Berkshire pigs.     

Selection and characterization of broad‐spectrum antibacterial substance‐producing Lactobacillus curvatus PA40 as a potential probiotic for feed additives

Lactic acid bacteria were screened for potential probiotics for use as feed additives. We obtained 3,000 isolates from feces of: cattle, dogs, goats, and infants; milk; yogurt; cheese; fermented sausages; Kimchi; and Cheonggukjang and tested their antibacterial activity toward indicator pathogens, including Bacillus cereus, Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella enterica Enteritidis. We further tested their tolerance to artificial gastric juice (1% [w/v] pepsin, pH 2.5) and bile acid (0.1% [w/v] oxgall, pH 6.8). Six isolates exhibited strong antibacterial activity against indicator pathogens. The PA40 isolate from Kimchi exhibited marked resistance to artificial gastric juice and bile acid. The antibacterial substances produced by PA40 were stable to heat, pH, and enzymes. Strain PA40 was identified as a Lactobacillus curvatus strain using chemical tests and 16S rDNA sequencing and produced 248.4 mmol/L lactic acid after 48 hr of fermentative growth. The L. curvatus PA40 strain was also highly tolerant of the artificial gastrointestinal model system. Our results indicate that L. curvatus PA40 could be used as a potential probiotic feed additive.     

Performance,health and behaviour of organic growing-finishing pigs in two different housing systems with or without access to pasture

Abstract

The effects of two housing systems (deep litter and straw-flow), with and without access to pasture during the summer period, were studied in an organic growing-finishing pig herd. Performance, health, skin lesions and daytime pig activity were studied in 29 pens of 16 pigs (total of 464 pigs, in 4 batches). Data from 21 pens were used for comparisons of deep litter and straw-flow and data from 16 pens for comparisons of access/no access to pasture. Pigs in the deep litter system had a lower carcass meat percentage (56.6% vs. 57.3%) and more locomotion problems (4.4% vs. 0%) than pigs in the straw-flow system. No difference in daytime pig activity was detected between the two housing systems. Under moderate temperatures, pigs with access to pasture and fed a commercial organic feed inside the building were not more active during daytime behaviour studies (7.30?h–16.30?h) than pigs without access to pasture. However, at 17 weeks of age the pigs with pasture access spent 21% of their time on pasture, less time inside the pig house (20% vs. 33%) and less time on the outside concrete area (4% vs. 12%) than the pigs without pasture. No difference in performance was detected between pigs with and pigs without access to pasture.     

Influence of l‐carnitine and l‐arginine on protein synthesis and maturation of the semitendinosus muscle of lightweight piglets

Lightweight (LW ) piglets from large litters display impaired growth performance compared with heavier littermates. This study investigated the growth performance and muscle development of early‐weaned LW piglets (birthweight <1.2 kg) from large litters (17.3 ± 3.0 total born per litter), fed ad libitum a milk replacer supplemented with either l ‐carnitine (CAR ) or l ‐arginine (ARG ) from day 7 to day 28 of age. In total, 36 female and entire male Swiss Large White piglets, weaned on day 7 of age, were artificially reared in pairs in rescue decks. They were allocated to one of three dietary treatments: unsupplemented control (CON ), 0.48 g l ‐carnitine·piglet^?1·day^?1 (CAR ) or 1.20 g l ‐arginine·kg body weight^?1·day^?1 (ARG ). Milk replacer was prepared daily in a 1:4 powder‐to‐water ratio and fed ad libitum. Piglets were weighed at birth and on days 7, 14, 21 and 28. Feed intake was assessed daily. Piglets were euthanized on day 28. The entire semitendinosus muscle (STM ) was collected, and organs were weighed. Subsequently, the STM was divided into the light (STM _l) and dark (STM _d) portion, and contractile and metabolic traits were analysed by ATP histochemistry, enzyme activities and gene expression. No differences in growth performance, organ and STM weight and on contractile traits were found between groups. A tendency (p  <  .10) for an elevated lipid oxidation enzyme activity in the STM _l and STM _d and greater (p  <  .05) phosphorylation of the mammalian target of rapamycin pathway in the STM _l of CAR compared with CON piglets was found. Despite these metabolic responses, the lack of effect of CAR and ARG supplementation on growth performance suggests that providing the milk replacer ad libitum in combination with added CAR and ARG is insufficient for eliciting faster growth of LW piglets.     

Effect of poultry litter biochar diet inclusion on feed manufacture and 4- to 21-d broiler performance

Decreasing diet cost and minimizing environmental impact are current issues that can affect the success of poultry production. In the eastern United States, much concern has been generated surrounding eutrophication of the Chesapeake Bay due to nitrogen and phosphorus leaching from land application of litter. Gasification of poultry litter and feeding the resultant poultry litter biochar (PLB) may be an alternative to traditional land application of litter. In addition, PLB may provide a cost-effective source of essential nutrients for poultry by the partial or complete replacement of rock phosphorus in poultry diets, and may also provide a mechanism for improving feed manufacture variables. The objectives of this study were to assess effects of diet incorporation of PLB on feed manufacture and pellet quality (Study 1) and subsequent feeding effects on broiler performance and tibia ash (Study 2). Seven diets were formulated to compare the replacement of rock phosphorus with PLB. Inclusion of PLB was high, 6.2 or 6.9%, in order to maximize rock phosphorus replacement but also to assess potential detriments. Four diets were chosen to generate replicated feed manufacture and pellet quality data. The addition of PLB to diets was shown to improve pellet quality (P < 0.05). Diets containing PLB decreased live weight gain and FCR; however, a positive yet modest contribution to bone mineralization was demonstrated (P < 0.0001). Therefore, PLB contains available phosphorus and calcium; however, the bioavailability of these minerals relative to rock phosphorus was not equivalent. Furthermore, the particular PLB tested decreased broiler performance.     

The Effect of High Total Ammonia Concentration on the Survival of Channel Catfish Experimentally Infected with Flavobacterium columnare

Abstract

Ammonia concentrations in water can affect the severity of Flavobacterium columnare infections in fish. Two trials lasting 7 d each were conducted to determine the effect of a single immersion flush treatment of total ammonia nitrogen (TAN; 15 mg/L) on the survival of channel catfish Ictalurus punctatus infected with F. columnare; the chemical was added while the water flowed continuously through the tanks. Both trials consisted of four treatments: (1) no ammonia exposure and no bacterial challenge (control), (2) ammonia exposure only, (3) bacterial challenge only, and (4) both ammonia exposure and bacterial challenge. Two hours after exposure to ammonia, the highest un-ionized ammonia level was 0.43 mg/L. The percent un-ionized ammonia is based on TAN, temperature, and pH. Caudal fins from three fish in each treatment were sampled at 24 h posttreatment to be analyzed by quantitative real-time polymerase chain reaction (qPCR). No significant difference in survival (mean ± SE) was noted between the channel catfish in treatment 1 (95.2 ± 1.2%) and those in treatment 2 (95.6 ± 1.0%); however, survival in both treatments 1 and 2 differed significantly from that in treatments 3 (8.5 ± 4.5%) and 4 (41.8 ± 12.7%). Treatment 4 catfish had significantly higher survival than treatment 3 catfish. Quantitative PCR data showed that treatment 4 fish had significantly less F. columnare (7.6 × 10⁵) than did treatment 3 fish (1.2 × 10⁷), and treatment 2 fish (8.5 × 10³) had significantly less bacteria than did treatment 1 fish (6.9 × 10⁴), indicating that ammonia limited the F. columnare infection. The highest mean concentration of the bacteria (3.9 × 10⁷) was found on moribund fish. The ammonia concentrations tested did not negatively influence fish survival but interfered with the infection process. An in vitro assay was also conducted to evaluate the direct effects of ammonia on F. columnare.

Received September 15, 2010; accepted May 7, 2011     

内蒙古白绒山羊产羔数遗传评估的研究

本研究旨在对内蒙古白绒山羊产羔数进行遗传评估,进一步提高其繁殖性能.试验数据来源于内蒙古白绒山羊种羊场1998-2013年的繁殖性能记录,首先,利用SAS软件的GLM程序确定影响产羔数的固定效应;其次,应用重复力动物模型的约束最大似然法(REML)估计产羔数的遗传力,该模型中考虑的随机效应包括个体加性效应和母体永久环境效应.结果表明,母羊年龄和产羔年份对产羔数影响极显著(P< 0.01),群对产羔数影响显著(P< 0.05),其他因素均不显著(P >0.05).产羔数的遗传力为0.13,属于中等偏低遗传.表明根据表型直接选择,产羔数的遗传进展可能会慢一些.     

The effects of the supplementation of Bacillus subtilis RX7 and B2A strains on the performance,blood profiles,intestinal Salmonella concentration,noxious gas emission,organ weight and breast meat quality of broiler challenged with Salmonella typhimurium

An experiment was conducted to evaluate the effects of B. subtilis RX7 and B. subtilis B2A on growth performance, blood profiles, intestinal Salmonella population, noxious gas emission, organ weight and breast meat quality of broilers under S. typhimurium challenge. A total of 120, one‐day‐old Ross 308 male broiler chicks were assigned to four dietary treatments, composed of six replications, with five birds per replication, for 10 day. The dietary treatment groups were negative control (NC; no antibiotic, no B. subtilis), positive control (PC; NC + 0.1% virginiamycin), B. subtilis RX7 (NC + 0.1% B. subtilis RX7 1.0 × 10⁹ cfu/g) and B. subtilis B2A (NC + 0.1% B. subtilis 1.0 × 10⁹ cfu/g). All birds were orally challenged with 2 ml suspension, containing 10⁴ cfu/ml of S. typhimurium KCCM 40253. Results indicated that the body weight gain, feed intake and feed conversion did not differ, among all comparative treatments. Serum haptoglobin concentration was lower in Bacillus treatments (RX7 + B2A) than the NC treatment (p < 0.05). Intestinal and excreta Salmonella number, and excreta ammonia gas emission in the PC treatment or Bacillus treatments, was lower than the NC treatment (p < 0.05). Breast pH, colour and water‐holding capacity were not affected by supplementation of B. subtilis RX7 and B2A. However, drip loss at 1 day post‐slaughter from birds fed with B. subtilis RX7 and B2A decreased, compared with the positive control birds (p < 0.05). Relative gizzard weights of birds fed B. subtilis RX7 and B2A were significantly higher than the NC birds under S. typhimurium challenge. It is concluded from the results that B. subtilis RX7 and B2A increased the gizzard weight and decreased the intestinal and excreta Salmonella population and excreta ammonia gas, and drip loss of breast meat after being stored for 1 day, under stress caused by the S. typhimurium challenge.