The potential of Clostridium autoethanogenum,a new single cell protein,in substituting fish meal in the diet of largemouth bass(Micropterus salmoides):Growth,feed utilization and intestinal histology

This study investigated the effects of replacing fishmeal with Clostridium autoethanogenum protein(CAP)on growth,feed utilization and intestinal histology of largemouth bass(Micropterus salmoides).The control diet contained 350 g/kg fishmeal,and then dietary fishmeal was decreased to 300 g/kg,250 g/kg,200 g/kg,150 g/kg and 100 g/kg by CAP inclusion,respectively(FM-30,FM-25,FM-20,FM-15,FM-10).The largemouth bass(110.0±1.0 g)were fed one of the six diets for 8 weeks.The groups of FM-30,FM-25 and FM-20 showed the similar weight gain(WG)and feed conversion ratio(FCR)to the control(P>0.05),while the WG of FM-10 group was decreased by 15.9%,and FCR increased by 0.12 when compared to the control(P<0.05).FM-15 and FM-10 groups had lower protein retention,lower villus height in intestine and higher serum malondialdehyde content than the control(P<0.05).The protease activity in FM-20,FM-15 and FM-10 groups was lower than that in the control(P<0.05),but no difference was observed in crude protein digestibility among groups(P>0.05).In conclusion,CAP could replace 150 g/kg fishmeal in diet(350 g/kg fishmeal)without adverse effects on growth,feed utilization and intestinal histology of largemouth bass.

Effect of dietary cottonseed meal on growth performance, physiological response, and gossypol accumulation in preadult grass carp, Ctenopharyngodon idellus

Cottonseed meal(CM) was used at up to 36.95% content in the diet(replacing 60% of dietary fish meal protein) without any negative effects on growth performance of pre-adult grass carp(initial body weight,761 g) under outdoor conditions.A culture trial was conducted in net cages installed in a large concrete pond.Seven isonitrogenous and isoenergetic diets containing a gradient of CM concentrations(0,12.2%,24.4%,36.6%,48.8%,54.8%,and 61.0%) as replacement for dietary fish meal protein(0,20%,40%,60%,80%,90%,and 100%) were formulated.Dietary non-resistant starch(from maize) was inverse to dietary CM.Growth performance and feed utilization of fish fed the diets containing CM replacing 0-40% fishmeal protein were not affected after the 6-week feeding trial.Accumulation of hepatopancreatic total gossypol in the hepatopancreas was significantly correlated with free gossypol content in the diets(HTG=88.6+1.5×DFG,R^2=0.89,P<0.05).Intestinal a-amylase and γ-glutamyl transpeptidase activities rose along with increasing dietary CM level.The structure of the mid-intestinal tissues and the ultrastructure of the enterocyte microvilli were normal when dietary CM was <36.6%(60% protein replacement).Increasing dietary CM content increased serum alanine aminotransferase levels but decreased serum alkaline phosphatase,cholesterol,high-density lipoprotein cholesterol,low-density lipoprotein cholesterol,triglycerides,and albumin(P<0.05).

Dietary supplementation of yeast cell wall improves the gastrointestinal development of weaned calves

The purpose of this study was to investigate the potential benefits of yeast cell wall(YCW)on the gastrointestinal development of weaned calves.Twenty healthy Holstein male calves(BW=92±8.29 kg and 60±5 d of age)were randomly allocated into 2 groups:CON with no YCW,and YCW(accounted for0.16%of the basal diet).The dietary concentrate-to-roughage ratio was 40:60.All the calves were fed regularly twice a day at 09:00 and 16:00 and had free access to water.The experiment lasted for 60 d.The results showed that calves fed YCW showed higher(P<0.05)length,width,and surface area of papillae in the ventral sac of the rumen as compared to CON.For the dorsal sac of the rumen,the muscularis thickness was thicker(P<0.05)in the YCW group when compared with CON group.The villus height of YCW calves was higher(P<0.05)than that of CON in the ileum.Calves supplemented with YCW also showed a higher(P<0.05)villus height-to-crypt depth ratio in the ileum.The YCW calves exhibited a greater(P<0.05)thickness of the wall in the duodenum and jejunum.Calves supplemented with YCW improved(P<0.05)the claudin 1 mRNA expression in the ileum and occludin mRNA expression in the jejunum and ileum.The YCW increased(P<0.05)the contents of secretory immunoglobulin A in the jejunum and ileum of calves.In conclusion,dietary supplementation with YCW could improve the gastrointestinal development of weaned calves.

Effects of three positively buoyant dietary supplements on the buoyancy of feces,growth and intestinal health of Tilapia,Oreochromis niloticus
O.aureus

Two trials were conducted to evaluate the effects of positively buoyant dietary materials on growth,intestinal health,and fecal properties of tilapia.In trial 1,ten diets containing 0(control)1%,2%or 3%cork,expanded and vitrified microball or expanded vermiculilite fine particles(250e450 mm)were fed to tilapia fry(5.0±0.1 g)for 30 days to evaluate the effects on the growth and feeding efficiencies.In trial 2,the three buoyant materials with coarse particles(450e830 mm)were included in diets at 0(control),3%,4%or 5%supplementation levels to feed tilapia juveniles(55.0±1.0 g),and the growth,feed efficiencies,evacuation velocity,fecal floatability and intestinal histology were examined after 21 days feeding.In trial 1,the weight gain(WG)of the fish significantly decreased with the supplementation of 2%,3%cork,3%microball or 3%vermiculite(P<0.05),and the feed conversion ratio(FCR)was significantly increased by 3%cork and 3%vermiculite(P<0.05)when compared to the control.In trial 2,cork-fed groups were observed to have more floating feces than microball-and vermiculite-fed groups.Dietary cork significantly decreased the sinking velocity of diets and feces(P<.05),but microball only decreased the sinking velocity of diets,and vermiculite(4%,5%)decreased the sinking velocity of feces(P<0.05).All buoyant materials supplemented groups showed lower WG and higher FCR than the control(P<.05).The intestine evacuation velocity and villus height,crypt depth,muscle thickness of intestinal walls were decreased by the increasing buoyant materials in diets,and 5%microball group showed the lowest values among all groups.In conclusion,dietary cork,microball and vermiculite(3%e5%)negatively affect the growth performance and intestinal histology of tilapia,and diets with cork supplementation could decrease the density of feed and feces to produce floating feces.

Efficacy of phytogenic extracts on growth performance and health of tilapia (Oreochromis niloticus × O. aureus)

The present study was conducted to evaluate the efficacy of phytogenic extract on growth and health of tilapia.Three experimental diets were designed as the basal diet(Con)and phytogenic extract(Flourishing,F)supplemented diets at 0.5 and 1 g/kg inclusion(F-1 and F-2),which the phytogenic additive was extracted from Eucommia ulmoides,Astragalus membranaceus,Lonicera japonica and Codonopsis pilosula.The three diets were fed to juvenile tilapia(14.0±0.1 g)with 30 fish per cage,and three replicate cages from the three groups were placed in one indoor concrete pool(a total of three pools were used).After 8 weeks of feeding,the weight gain was significantly increased,and feed conversion ratio was decreased in F-2 group(P<0.05)when compared to the control.Both levels of phytogenic extract significantly promoted the retentions of protein and lipid and the apparent digestibility coefficient of dry matter and protein(P<0.05).The activity of superoxide dismutase and the levels of white blood cells,haemoglobin and glutamic pyruvic transaminase were also significantly increased by the supplementation of phytogenic extract(P<0.05).The villus height in anterior intestine was significantly enhanced in F-1 and F-2 groups(P<0.05).After challenging with Aeromonas hydrophila,the cumulative mortality was significantly declined in F-1 and F-2 groups(P<0.05).In summary,the dietary supplementation of phytogenic extract at 1 g/kg feed could provide positive efficiency on growth,nutrient utilization,immunity,gut morphology and disease resistance of tilapia under the present conditions.