A study of the mechanisms of probiotic effect of Bacillus subtilis strain 8130

The wild-type Bacillus subtilis strain 8130 secreted metabolites that stimulated two to three times the growth of the test cultures of lactic acid bacteria. It exhibited endoglucanase activity that depended on the composition of nutrient medium. The addition of the product of two-stage culturing of B. subtilis 8130 to the diet of pigs (0.2% of fodder weight) made it possible to increase the daily weight gain by 19% and decrease the consumption of mixed fodder by 10%. Digestion of protein, fat, and other organic compounds increased by 3–4% and cellulose by 12%. It was shown that B. subtilis 8130 is a probiotic with targeted action stimulating digestion (primarily the digestion of cellulose). The enrichment of a dry-beer pellet with the product of solid-phase fermentation by bacillus (1 × 10⁸ cells per gram dry pellet) allowed the pellet to entered into the diet of a calf (6% of the weight of fodder with probiotic), causing additional weight gain by 12% and a 10% economy of fodder consumption.     

Effect of the probiotic Bacillus subtilis on the growth and food utilization of tilapia (Oreochromis niloticus) and prawn (Macrobrachium rosenbergii) under laboratory conditions

Three experiments were conducted to analyze the effect of the probiotic Bacillus subtilis on the growth of juvenile tilapia (Oreochromis niloticus) and freshwater prawn (Macrobrachium rosenbergii). The experiments were conducted under laboratory conditions, minimizing the indirect effects of the probiotic on the water quality and leaving only the possible bactericidal and digestion-support effects. A model of stress was also designed in tilapia to compare the effect with tilapia under normal conditions. The dose in the food was 0.1% of the probiotic (5 x 10(8) CFU/g and 99.9 % maltrine) in the dry diet. Every 14 days the animals were weighed in group (tilapias +/- 0.1 g, prawns +/- 0.001 g) to estimate average body weight. In the first experiment (tilapia) the specific growth rate (SGR) and the feed conversion ratio (FCR) were bad in relation with the factor probiotic, but the differences were not significant. In the second experiment (tilapia) both the SGR and the FCR deteriorated with the addition of B. subtilis to the diet; the difference was significant to 94%. The stress factor, on the contrary, caused a notable worsening of both the growth and the food utilization. In the experiment with prawns the addition of B. subtilis caused a light deterioration of the growth and of the food utilization, with a statistical probability of mistake of 10% in case of the growth. During the experiment the direct effects over the digestive system should have prevailed, either by the contribution of macro- and micronutrients, or by the enzymes that contribute to the digestion. The negative effect due to the addition of the probiotic to the food was small (about 10% in both the SGR and the FCR) being difficult to detect statistically. The reports on the positive action of probiotics on the growth in aquatic animals have been conducted mainly in ponds, and our information does not contradict directly a possible positive action of B. subtilis in this type of systems. Since the effect on the digestive system seems to be relatively small, in those environments the effect might be compensated by other positive effects on water quality, and by bactericidal effects on pathogenic bacteria.     

Effect of dietary supplementation of probiotic and vitamin C on the immune response of Indian major carp, Labeo rohita (Ham.)

The immunostimulatory effect of probiotics and vitamin C has been established in many systems including fish. An investigation was carried out to study the effect of dietary supplementation of a probiotic bacterium "Bacillus subtilis", vitamin C in the form of ascorbyl polyphosphate and their combination on the immune response of Indian major carp, rohu, (Labeo rohita Ham.) fingerlings fed for a period of 60 days. The total serum protein and globulin content was significantly higher (p<0.05) in probiotic (B. subtilis @ 10(8) CFU/g of the feed) fed group while the respiratory burst activity of blood neutrophils was significantly high in vitamin C (ascorbyl polyphosphate @100 mg per kg diet) fed group. The antibody level was significantly high in Bacillus subtilis treated group followed by the probiotic (B. subtilis @ 10(8) CFU/g of the feed) and ascorbyl polyphosphate (ascorbyl polyphosphate @100 mg per kg diet) combined group. The least percentage of mortality was recorded in B. subtilis treated group (25%) followed by 35 and 40% in ascorbyl polyphosphate treated and B. subtilis and ascorbyl polyphosphate combined groups, respectively.     

Special effects of a complex probiotic containing cellulolytic bacteria Cellulomonas on actively growing rabbits

It was shown that the association of probiotic bacteria of the genuses Bacillus and Cellulomonas form biolayers on the surface of beet marc particles. The positive effect of a fodder additive that contained the biolayer on the basis of a phytomatrix on the growth and development of young rabbits was shown. Feeding of animals with a mixed fodder that contained 0.1% preparation resulted in stimulation of digestion of all components of the food. Among other components of the mixed fodder, cellulose was digested most effectively. An increase in the biomass of symbiotic bacteria and enzymatic activity in the blindgut chymus was also observed. The positive nitrogen balance demonstrated an increase in the nitrogen content in animals and a decrease of its losses with excretion. The mechanism of response of the rabbit’s organism to introduction of the complex probiotic preparation into the digestive tract is discussed.     

Effects of Bacillus subtilis on the growth performance, digestive enzymes, immune gene expression and disease resistance of white shrimp, Litopenaeus vannamei

We studied the effect of two probiotic Bacillus subtilis strains on the growth performance, digestive enzyme activity, immune gene expression and disease resistance of juvenile white shrimp (Litopenaeus vannamei). A mixture of two probiotic strains, L10 and G1 in equal proportions, was administered at two different doses 10(5) (BM5) and 10(8)?(BM8)?CFU?g(-1) feed to shrimp for eight weeks. In comparison to untreated control group, final weight, weight gain and digestive enzyme activity were significantly greater in shrimp fed BM5 and BM8 diets. Significant differences for specific growth rate (SGR) and survival were recorded in shrimp fed BM8 diet as compared with the control; however, no significant differences were recorded for food conversion ratio (FCR) among all the experimental groups. Eight weeks after the start of the feeding period, shrimp were challenged with Vibrio harveyi. Statistical analysis revealed significant differences in shrimp survival between probiotic and control groups. Cumulative mortality of the control group was 63.3%, whereas cumulative mortality of the shrimp that had been given probiotics was 20.0% with BM8 and 33.3% with BM5. Subsequently, real-time PCR was employed to determine the mRNA levels of prophenoloxidase (proPO), peroxinectin (PE), lipopolysaccharide- and β-1,3-glucan-binding protein (LGBP) and serine protein (SP). The expression of all immune-related genes studied was significantly up-regulated (P?相似文献   

Food consumption and utilization responses to dietary dilution with cellulose and water by velvetbean caterpillars, Anticarsia gemmatalis

Abstract Dilution of an artificial diet with water or cellulose to nutrient levels of 32% (undiluted), 19% and 10% fresh weight (fw) resulted in increased fw and dry weight (dw) food consumption (both absolute amounts and weight-relative rates) by velvetbean caterpillars, Anticarsia gemmatalis Hübner. Despite these increases, the absolute amount and relative rate of nutrient intake by the caterpillars declined with dilution, as did their dw gain and dw (% fw) and lipid (% dw) contents. The proportion of consumed food (dw, including cellulose) that was digested and absorbed declined with increased dietary cellulose; however, the proportion of consumed nutrients (dw, excluding cellulose) that was digested and absorbed was not affected by the presence of cellulose, although it increased slightly (but significantly) with dietary water. The efficiency with which the absorbed nutrients were converted to biomass energy showed a negative relationship with the various measures of food consumption and thus a positive relationship with dietary nutrient level.
The compensatory increases in feeding mitigated the deleterious impact of dietary dilution on growth, which would have declined further without the increased feeding. These data suggest that food consumption is regulated primarily through an evaluation of food nutrient level, and that the metabolic costs associated with the increased consumption and processing of food may be substantial, especially on the most diluted diets. Another hypothesized cost of increased feeding, reduced efficiency of digestion and absorption as food presumably passes more rapidly through the gut, was not detected.     

Effect of probiotic CenBiot on the control of diarrhoea and feed efficiency in pigs

The production and testing of a probiotic formulated with a strain of Bacillus cereus (Probiotic CenBiot) is reported. The strain was grown in fed batch fermenters, desiccated, and mixed with cornflour. To test the effect of the probiotic in controlling piglet diarrhoea, two groups of sows and their respective litters received feed supplemented with probiotic CenBiot or Furazolidone; the control group received the same basic feed but not supplemented. Probiotic CenBiot was as effective as Furazolidone, reducing the prevalence of diarrhoea to half that in the control group. It also significantly improved feed conversion, daily weight gain and total weight gain in pigs in the nursery phase. Feed conversion ratios of weaned pigs were 1·904, 2·146 and 2·099 for the groups that received Probiotic CenBiot, a commercial probiotic, and basic feed, respectively. In terms of food consumption, the Probiotic CenBiot group consumed 12·6% less than the commercial probiotic group, and 10% less than the control group, to achieve the same weight.     

饲料中添加枯草芽孢杆菌对青鱼生长、消化酶活性和鱼体组成的影响

用不加枯草芽孢杆菌的对照饲料和分别添加2×10⁶、2×10⁷、2×10⁸和5×10⁸ cfu/g枯草芽孢杆菌的4种实验饲料, 分别喂养初始均重为(4.16±0.03) g的5组三重复的青鱼鱼种8周。饲养试验在15只容积为80 L循环式水簇箱内进行, 水温控制为(25±0.5) ℃。结果表明: 饲料中添加枯草芽孢杆菌的实验组青鱼鱼体终重和鱼体增重比不添加的饲料组显著提高, 而饲料系数则显著降低(P<0.05), 不同枯草芽孢杆菌添加量对青鱼鱼体增重和饲料系数均无显著影响(P>0.05)。饲料中添加枯草芽孢杆菌对青鱼的成活率无显著影响(P>0.05)。青鱼摄食添加枯草芽孢杆菌的实验饲料后其肠蛋白酶活性比不添加组显著升高(P<0.05), 并随着枯草芽孢杆菌添加量的增加而显著上升(P<0.05), 但添加量到2×10⁷ cfu/g后继续增加则不再显著变化(P>0.05)。青鱼摄食添加枯草芽孢杆菌的实验饲料后, 其肠淀粉酶活性均比不添加组显著升高(P<0.05), 且随枯草芽孢杆菌添加量增大呈不断升高的趋势。青鱼摄食添加2×10⁷、2×10⁸和5×10⁸ cfu/g枯草芽孢杆菌的饲料后, 其肝胰脏蛋白酶活性显著高于摄食不添加或添加2×10⁶ cfu/g枯草芽孢杆菌的实验组(P<0.05)。青鱼摄食添加枯草芽孢杆菌的实验饲料后, 其肝胰脏淀粉酶、肝胰脏脂肪酶和肠脂肪酶的活性均与不添加的实验组无显著差异(P>0.05)。青鱼鱼种摄食添加枯草芽孢杆菌的饲料与摄食不添加枯草芽孢杆菌的饲料相比, 其全鱼营养组成均无显著差异(P>0.05)。因此, 在实验条件下, 饲料中添加2×10⁶—5×10⁸ cfu/g的枯草芽孢杆菌能促进青鱼鱼种的生长和降低饲料系数, 而对鱼体组成没有影响。     

枯草芽孢杆菌对草鱼肝脏脂质代谢的调节作用

为研究益生枯草芽孢杆菌(Bacillus subtilis)对草鱼(Ctenopharyngodon idella)肝脏脂质代谢及抗氧化功能的影响, 实验设置对照组(Con组)、Aeromonas hydrophila组(Ah组)、Aeromonas hydrophila+Bacillus subtilis组(Ah+Bs组)、Bacillus subtilis+Aeromonas hydrophila组(Bs+Ah组), 三个实验组均腹腔注射1×105 CFU/fish嗜水气单胞菌(Aeromonas hydrophila), 枯草芽孢杆菌饲料含菌量为1×107 CFU/g, 实验周期为56d, 并于第28和第56天取样。结果表明, 与Ah组相比, 投喂枯草芽孢杆菌饲料后, (1)体增重率、特定生长率显著增加(P<0.05); (2) 28d时肝脏油红O染色脂滴面积及脂肪含量显著下降(P<0.05); (3)调节血脂代谢及缓解肝脏损伤: 血清胆固醇、甘油三酯、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇含量升高, 谷草转氨酶和谷丙转氨酶活性显著降低(P<0.05); (4)调节脂质代谢: 28d时乙酰辅酶A羧化酶的表达水平下调, 脂蛋白脂酶及脂肪甘油三酯脂肪酶的表达水平上调; (5)增强肝脏抗氧化能力、减少脂质过氧化的发生: 肝脏超氧化物歧化酶、过氧化氢酶、谷胱甘肽、总抗氧化能力提高; 丙二醛及过氧化氢含量降低。综上, 在饲料中添加益生枯草芽孢杆菌可以增强草鱼的抗氧化能力, 缓解机体因嗜水气单胞菌感染造成的肝脏损伤, 调节肝脏脂质代谢功能, 减少脂质在肝脏中的积累, 并促进草鱼的生长。     

Synthesis of peptidoglycan by high molecular weight penicillin-binding proteins of Bacillus subtilis and Bacillus stearothermophilus

The high molecular weight penicillin-binding proteins (PBP(s) ) Bacillus subtilis PBPs 1, 2, and 4 and Bacillus stearothermophilus PBPs 1-4 were shown to catalyze peptidoglycan synthesis from the undecaprenol-containing lipid intermediate substrate in two assay systems. In a filter paper assay system, high levels of substrate polymerization occurred when reaction mixtures were incubated on Whatman 3MM filter paper. The pH optimum for peptidoglycan synthesis was 7.5 for B. subtilis PBPs 1, 2, and 4 and 8.5 for B. stearothermophilus PBPs 1-4. Polymerization was Mg2+-independent and was unaffected by sulfhydryl reagents. Reconstitution with membrane lipids or addition of detergent (optimal concentration, 0.1%) was necessary for synthesis to occur. Bacitracin, penicillin, and cephalothin did not affect polymerization while vancomycin, ristocetin, moenomycin, and macarbomycin were strong inhibitors. In a test tube assay system, optimal synthesis occurred either in the presence of 10% ethylene glycol, 10% glycerol, and 8% methanol or in the presence of 10% N-acetylglucosamine. The products of lysozyme digestion of the synthesized peptidoglycan were analyzed by gel filtration and paper chromatography. B. stearothermophilus PBPs 1-4 synthesized a peptidoglycan product that was 5-7% cross-linked. No evidence for cross-linking was apparent in the peptidoglycan product of B. subtilis PBPs 1, 2, and 4.     

Response of performance characteristics and fecal consistency to long-lasting dietary supplementation with the probiotic strain Bacillus cereus var. toyoi to sows and piglets

As part of an interdisciplinary research project, we studied the performance response of sows and their litters to the probiotic strain Bacillus cereus var. toyoi as well as feces consistency of piglets. Gestating sows (n=26) were randomly allotted into two groups. The probiotic B. cereus var. toyoi was administered by dietary supplementation to one group of sows and their respective litters (probiotic group) whereas the second group (control group) received no probiotic supplementation. The duration of the application was nearly 17 weeks for sows (day 90 ante partum until day 28 post partum) and six weeks for piglets (day 15-56). Piglets were weaned after 28 days. Body weight and feed consumption were recorded weekly and fecal consistency of weaned piglets was studied daily. B. cereus var. toyoi was recovered from feces of sows and piglets as well as from digesta of piglets in the probiotic group, while being absent from all samples of control animals. In addition, the probiotic was detected in piglet feces and digesta before pre-starter feed was offered, indicating a second route of uptake besides diet. Sows of the probiotic group nursed numerically more piglets and supported a higher sum of total nursing days of all piglets within each litter than control sows (p = 0.04). In turn, body weight (BW) up to day 35 was greater for control piglets (p < 0.01), while average daily gain and gain to feed ratio (G:F) in weeks six and eight postweaning was higher in the probiotic group (p < 0.05). The overall G:F of the total postweaning period was 680 g/kg and 628 g/kg in the probiotic group and control group, respectively (p = 0.009). During the trial a high prevalence of liquid feces with its maximum in the second week after weaning was observed. Probiotic supplementation led to a reduction in the incidence of liquid feces and postweaning diarrhea by 38% and 59%, respectively (p < 0.001).     

Effects of potential probiotic Bacillus subtilis T13 on growth, immunity and disease resistance against Vibrio splendidus infection in juvenile sea cucumber Apostichopus japonicus

A feeding experiment was conducted to determine influences of potential probiotic Bacillus subtilis T13 (isolated from intestine of healthy sea cucumbers) on growth, immunity and disease resistance against Vibrio splendidus infection in juvenile sea cucumbers Apostichopus japonicus. Animals were fed with diets containing B. subtilis T13 at 0, 10(5), 10(7) and 10(9) CFU/g for 30 days, respectively. At the end of the growth trial, fifteen sea cucumbers from each aquarium were sampled for immune indices measurement. Then twenty sea cucumbers from each replicate were challenged with V. splendidus. Results showed that administration of B. subtilis T13 had significant effect on the specific growth rates (SGR) of sea cucumbers (P < 0.05). Phagocytosis, respiratory burst activity and total nitric oxide synthase (T-NOS) activity were significantly improved in coelomocytes of sea cucumbers fed with T13 at 10(9) CFU/g diet (P < 0.05). The highest values of the total coelomocytes counts (TCC) and superoxide dismutase (SOD) activity were found in sea cucumbers fed diet containing T13 at 10(9) CFU/g. The cumulative mortality after V. splendidus challenge decreased significantly in sea cucumbers fed with T13 at dose of 10(9) CFU/g (P < 0.05). The present study confirmed the potential beneficial effects of B. subtilis T13 as dietary probiotic in juvenile A. japonicus.     

Effect of probiotic CenBiot on the control of diarrhoea and feed efficiency in pigs

The production and testing of a probiotic formulated with a strain of Bacillus cereus (Probiotic CenBiot) is reported. The strain was grown in fed batch fermenters, desiccated, and mixed with cornflour. To test the effect of the probiotic in controlling piglet diarrhoea, two groups of sows and their respective litters received feed supplemented with probiotic CenBiot or Furazolidone; the control group received the same basic feed but not supplemented. Probiotic CenBiot was as effective as Furazolidone, reducing the prevalence of diarrhoea to half that in the control group. It also significantly improved feed conversion, daily weight gain and total weight gain in pigs in the nursery phase. Feed conversion ratios of weaned pigs were 1.904, 2.146 and 2.099 for the groups that received Probiotic CenBiot, a commercial probiotic, and basic feed, respectively. In terms of food consumption, the Probiotic CenBiot group consumed 12.6% less than the commercial probiotic group, and 10% less than the control group, to achieve the same weight.     

Improvement in the growth performance of white shrimp, Litopenaeus vannamei, by a protease-producing probiotic, Bacillus subtilis E20, from natto

Aims:  To isolate and identify a benefic bacterium, Bacillus subtilis E20, from natto (fermented soybeans), and incorporate it into shrimp feed to promote shrimp growth performance.
Methods and Results:  A protease-producing bacterium, E20, isolated from natto was identified as B. subtilis by an API 50 CHB kit and the 16S rDNA sequence. B. subtilis E20 was able to grow at a broad range of temperatures (10–50°C), pH values (5–10), and NaCl levels (0–9%). The best culture conditions for B. subtilis E20 to produce the protease were 40°C, a pH of 6–8 and 0% NaCl. No shrimp died after being injected with B. subtilis E20 [up to 10⁹ colony-forming units (CFU) per shrimp]. Bacillus subtilis E20 was incorporated in diets at the levels of 0 (control), 10⁶, 10⁷, and 10⁸ CFU kg⁻¹ for shrimp grow-out culture, and results showed that after feeding on B. subtilis E20-containing diets (10⁸ CFU kg⁻¹ of diet), shrimp had excellent growth performance and production compared to the control because protease activities in the digestive tract were improved by B. subtilis E20.
Conclusions:  Bacillus subtilis E20 isolated from natto is a great protease producer and is able to improve shrimp growth performance through increasing the digestibility of food.
Significance and Impact of the Study:  Results suggest that B. subtilis E20 is a potential candidate for use as a probiotic to improve shrimp growth performance, and consequently reduce feed costs.     

Increases in immune parameters by inulin and Bacillus subtilis dietary administration to gilthead seabream (Sparus aurata L.) did not correlate with disease resistance to Photobacterium damselae

The present work evaluates the effects of inulin and Bacillus subtilis, single or combined, on immune parameters, immune-related gene expression and protection against Photobacterium damselae subsp. piscicida in gilthead seabream (Sparus aurata). Three trials were conducted. In the first trial, different concentrations of inulin (10, 15 and 30 g kg(-1)) (as a prebiotic) were administered to determine the optimal concentration for stimulating the seabream's immune system. In the second trial, the optimum concentration of inulin (10 g kg(-1)) was combined with B. subtilis (as a probiotic). Following two and four weeks of the treatment, the main immune parameters, as well as the expression of seven immune-related genes, were measured. In the final trial, fish fed the same diet as in the second trial were challenged intraperitoneally with P. damselae subsp. piscicida (10(9) cfu g(-1)). Treatment groups for the second and third trial were control (non-supplemented diet), inulin (10 g kg(-1)), B. subtilis (10(7) cfu g(-1)) and inulin + B. subtilis (10 g kg(-1) and 10(7) cfu g(-1) respectively). Dietary administration of inulin or B. subtilis for two weeks stimulated the serum complement activity and the IgM level, as well as leucocyte phagocytic activity; furthermore, inulin stimulated leucocyte respiratory burst activity. When inulin and B. subtilis were administered together (as a synbiotic), only the serum complement activity and the IgM level increased in a statistically significant manner. Furthermore, the complement activity showed a significant increase in fish fed the three experimental diets for four weeks. The challenge experiment showed that the fish fed inulin or the synbiotic diet had non-significantly lower or significantly higher cumulative mortality, respectively, compared with the control group (non-supplemented diet). These results suggest that inulin and B. subtilis modulate the immune response of the gilthead seabream, although the combined administration increases susceptibility to infection by P. damselae subsp. piscicida.     

Compensatory responses of the fall armyworm (Spodoptera frugiperda) when fed water- and cellulose-diluted diets

Abstract Caterpillars of the noctuid moth, Spodoptera frugiperda (J. E. Smith), reared on artificial diets diluted with cellulose and water, increased fresh weight (fw) consumption 2.2–2.5-fold over those on the undiluted diet. At moderate levels of water- or cellulose-dilution, the increased consumption, combined with increased digestion and absorption of nutrients (ADNU), sufficiently compensated for the reduced nutrient intake to achieve pupal biomass equivalent to that of pupae from the undiluted diet. At higher levels of water- and cellulose-dilution, fw consumption and ADNU increased further but pupal dry weight declined on the water-diluted diets. At each level of dilution fw consumption and ADNU increased similarly on the water- and cellulose-diluted diets, but biomass gain was reduced on the water- compared with the cellulose-diluted diets. This was due in part to lowered food conversion efficiency on the water-diluted diets, possibly caused by increased costs of metabolizing the wetter diets. Our data support the hypothesis that consumption rates are regulated by a nutrient feedback mechanism. Our data also suggest that digestive enzyme activity is correlated with consumption. Furthermore, the cost of increased consumption rates on diets of reduced energetic value may constitute a substantially greater energy expenditure than previously believed. However, this cost was insufficient to reduce relative growth rates but was apparently manifested in lowered lipid accumulation.     

Growth rate of tank-reared Mediterranean amberjack, Seriola dumerili (Risso 1810) fed on three different diets

Mediterranean amberjack Seriola dumerili (Risso 1810) has aquaculture potential. The growth rate and food conversion ratio of S. dumerili on three different types of food (A: 100% frozen sardines; B: 50% frozen sardines and 50% pellet; C: 100% pellet) were measured, and analysed with respect to temperature, condition index and chemical composition of the fish fillet. Wild S. dumerili, average body weight 248 g and average total length 26.9 cm were caught in August and September 1994 in the South Adriatic Sea near Dubrovnik, Croatia and kept in three tanks (n=15 in each tank; duration of experiment, 226 days). The fish that were fed on diet A [initial weight, 252 ± 71 g; total length (TL), 24.3 ± 2.6 cm] started feeding immediately; however, fish assigned to diet C began to feed entirely on the pelleted diet 1 month after the start of the experiment. The mortality of fish fed on diet A was negligible, the registered growth rate was 313 ± 74 g (124.2%), specific growth rate was 0.32% day^?1 and the food conversion rate was 6.7. The fish fed on diet B (initial weight, 246 ± 74 g; TL, 28.2 ± 2.5 cm) started to feed on day 3 and achieved a total growth rate of about 98% (final weight gain, 241 ± 69 g) and specific growth rate of 0.24% day^?1 (feed conversion rate of 9.00 and mortality 13%). The fish fed on diet C (initial weight, 246 ± 74 g; TL, 28.2 ± 2.5 cm) started to feed on the pellets after 1 month and had a growth rate of 87% (weight gain 214 ± 85 g), a specific growth rate of 0.24% day^?1 and a food conversion rate of 10.6 with considerable mortality (27%). In all three diet groups the fish grew with considerable variation in food consumption and growth rate, depending on seasonal temperature variations of the ambient sea water supplied to the rearing tanks. Chemical analysis showed that the protein level (amount) in the fish meat exceeded 20% in all three fish fillet samples.     

Proteolysis in vitro as the Way of Modification of the Protein Trophic Component

The protein hydrolysates of two types, fodder and for microbiological medium, have been obtained in vitro, using protein containing wastes of Iceland scallop fishery (WSF) and enzyme preparation from the red king crab hepatopancreas. The degree of protein degradation and composition of obtained hydrolysates were analyzed. Intensive protein hydrolysis was necessary to obtain the microbiological diagnostic cultural media that fit trophic requirements for 12 microbial test-cultures. Addition of the fodder protein hydrolysate to diet of juvenile salmons Salmo salar during mixed feeding produces a positive effect on their survival; the 5 and 20% replacement of fish flour by the fodder hydrolysate results in a reduction of fish mortality by 21 and 57%, respectively. The living weight of chickens increased by 15% after substitution of the 10% fish flour by the fodder WSF hydrolysate in their diet. The results obtained can be explained by a more effective assimilation of partly hydrolyzed proteins in comparison with native ones.     

Guar gum consumption in adolescent and adult rats: short- and long-term metabolic effects

Metabolic responses to short- and long-term guar gum consumption were studied in adolescent and adult rats. For the long-term study, male adolescent rats were divided into four groups (n = 60/group) and fed guar gum, cellulose, or bran diet for 67 weeks. Metabolic studies (food--water intake, feces--urine output, body weight, carbohydrate tolerance) were performed eight times during the 67 weeks. The guar gum group consumed less diet throughout the entire study and gained less weight over the first 20 weeks compared with the cellulose and bran groups. A second bran-fed group was food restricted over the first 20 weeks to match the reduced weight gain of the guar gum group and then fed ad libitum. Reduced plasma glucose excursions were measured for only the guar gum group after both fibre-free glucose and sucrose challenges at weeks 6, 12, and 18; from 24 to 64 weeks all four groups had similar glucose tolerance responses. Twenty-four hour urinary glucose excretion was similar during all eight metabolic studies up to 64 weeks for guar gum and cellulose groups. In the short-term study, male adolescent (200 g; n = 10/group) and adult (630 g; n = 15/group) rats were divided into five and four groups, respectively, and fed guar gum, guar by-product (GBP), cellulose, or bran diet for 6 weeks. A metabolic study was performed during the 6th week. Adolescent rats fed guar gum or GBP diets gained less weight than the cellulose group; only the guar gum group displayed improved carbohydrate tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of Phytate-Degrading Lactobacillus Culture Administration to Broiler Chickens

Probiotics have been demonstrated to promote growth, stimulate immune responses, and improve food safety of poultry. While widely used, their effectiveness is mixed, and the mechanisms through which they contribute to poultry production are not well understood. Microbial phytases are increasingly supplemented in feed to improve digestibility and reduce antinutritive effects of phytate. The microbial origin of these exogenous enzymes suggests a potentially important mechanism of probiotic functionality. We investigated phytate degradation as a novel probiotic mechanism using recombinant Lactobacillus cultures expressing Bacillus subtilis phytase. B. subtilis phyA was codon optimized for expression in Lactobacillus and cloned into the expression vector pTRK882. The resulting plasmid, pTD003, was transformed into Lactobacillus acidophilus, Lactobacillus gallinarum, and Lactobacillus gasseri. SDS-PAGE revealed a protein in the culture supernatants of Lactobacillus pTD003 transformants with a molecular weight similar to that of the B. subtilis phytase. Expression of B. subtilis phytase increased phytate degradation of L. acidophilus, L. gasseri, and L. gallinarum approximately 4-, 10-, and 18-fold over the background activity of empty-vector transformants, respectively. Phytase-expressing L. gallinarum and L. gasseri were administered to broiler chicks fed a phosphorus-deficient diet. Phytase-expressing L. gasseri improved weight gain of broiler chickens to a level comparable to that for chickens fed a control diet adequate in phosphorus, demonstrating proof of principle that administration of phytate-degrading probiotic cultures can improve performance of livestock animals. This will inform future studies investigating whether probiotic cultures are able to provide both the performance benefits of feed enzymes and the animal health and food safety benefits traditionally associated with probiotics.