Effect of dietary defatted diatom biomass on egg production and quality of laying hens

Background： This study was to determine if feeding laying hens with defatted diatom microalgal biomass （DFA） from biofuel production affected their egg production and health status. Methods： Five replicates of 5 individually caged ISA Babcock White leghorn hens were fed 4 diets, including a corn-soybean meal control diet, a diet containing 7.5% DFA substituting for soybean meal, and diets containing 7.5% or 15% DFA substituting for corn and soybean meal. Body weights, feed intake, feed conversion ratio （FCR）, rate of egg production, egg size, egg mass, and several characteristics of eggs were determined at 4 and 8 wk. Venous blood was sampled at 4 and 8 wk for measurement of 5 biomarkers of health. Results： The15% DFA diet decreased （P 〈 0.05） feed intake, egg production, and plasma uric acid concentrations as compared with the control diet, but increased （P 〈 0.05） egg albumen weight and height compared with the 7.5% DFA diets. The two levels of DFA produced dose-dependent （P 〈 0.05） changes in three color measures of egg yolk, without affecting four hen plasma biochemical indicators of health. Conclusions： Feeding laying hens with 7.5% DFA in the corn-soybean meal diet for 8 wk had no adverse effect on their health, egg production, or egg quality, but 15% inclusion reduced feed intake, egg production, and efficiency of feed utilization.

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.

Cloning and expression analysis of the nuclear factor erythroid 2-related factor 2(Nrf2)gene of grass carp(Ctenopharyngodon idellus)and the dietary effect of Eucommia ulmoides on gene expression

Nuclear factor erythroid 2-related factor 2(Nrf2)is an important transcription factor in the regulation of redox homeostasis,which plays a vital role in metabolism,the cell cycle,and cell protection.In this study,the complete cDNA sequence of Nrf2 gene of grass carp was obtained by rapid amplification of cDNA ends-polymerase chain reaction(RACE-PCR),and the characteristics of Nrf2 proteins predicted from gene sequencing were analyzed by bioinformatics methods.Tissue differential expression patterns were also detected by Real-time Fluorescence quantitative PCR(qRT-PCR).Then,Eucommia ulmoides(EU),a traditional Chinese medicine,was added into diet with an inclusion of 2%to feed grass carp for 3 months to investigate the effects on the expression of Nrf2 gene in tissues.The results showed that the full-length of Nrf2 gene of grass carp is 2760 bp,encoding 593 amino acids,and the predicted Nrf2 protein is a hydrophilic and non-secretory protein.Grass carp Nrf2 gene showed higher expression in kidney,gill,liver,spleen,and blood tissues than in other tissues.In the feeding trial,dietary EU significantly promoted the Nrf2 mRNA expression in kidney,gill,and liver tissues after three months feeding.The results suggest that Nrf2 plays an important role in the anti-oxidative capacity of grass carp and its expression is enhanced by dietary EU.

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.