Evaluation of the effect and profitability of gene-assisted selection in pig breeding system

Objective:To evaluate the effect and profitability of using the quantitative trait loci (QTL)-linked direct marker (DR marker) in gene-assisted selection (GAS). Methods: Three populations (100, 200, or 300 sows plus 10 boars within each group) with segregating QTL were simulated stochastically. Five economic traits were investigated, including number of born alive (NBA), average daily gain to 100 kg body weight (ADG), feed conversion ratio (FCR), back fat at 100 kg body weight (BF) and intramuscular fat (IMF). Selection was based on the estimated breeding value (EBV) of each trait. The starting frequencies of the QTL's favorable allele were 0.1, 0.3 and 0.5, respectively. The economic return was calculated by gene flow method. Results: The selection efficiency was higher than 100% when DR markers were used in GAS for 5 traits. The selection efficiency for NBA was the highest, and the lowest was for ADG whose QTL had the lowest variance. The mixed model applied DR markers and obtained higher extra genetic gain and extra economic returns. We also found that the lower the frequency of the favorable allele of the QTL, the higher the extra return obtained. Conclusion: GAS is an effective selection scheme to increase the genetic gain and the eco- nomic returns in pig breeding.

Effects of rearing temperature and density on growth,survival and development of sea cucumber larvae,Apostichopus japonicus(Selenka)

In laboratory conditions,effects of rearing temperature and stocking density were examined on hatching of fertilized egg and growth of auricularia larvae of Apostichopus japonicus respectively.Data series like larval length and density,metamorphic time,and survival rate of the larvae were recorded.Statistics showed that for A.japonicus,survival rate(from fertilized egg to late auricularia) decreased significantly with the increasing rearing temperature(P<0.05).At different temperatures SGR was statistically significant as well(P<0.05) from day 1,and maximal SGR was found on day 9 at 24℃(159.26±3.28).This study clearly indicated that at low temperature(<24℃),metamorphic rate was remarkably higher than at higher temperature(>26℃).Hatching rate was significantly different between 0.2-5 ind./ml groups and 20-50 ind./ml groups.Rearing larvae at the higher density had the smaller maximal-length,whereas needed longer time to complete metamorphosis.This study suggested that 21℃ and 0.4 ind./ml can be used as the most suitable rearing temperature and stocking density for large-scale artificial breeding of A.japonicus's larvae.

Effects of lithium on the survival,growth,and reproduction of Daphniopsis tibetana Sars(Crustacea:Cladocera)

We evaluated the effects of lithium on the survival, growth, and reproduction ofD. tibetana in the laboratory. The safe concentration value was 69.3 mg/L. The time to first brood was significant lower for individuals reared in 5 and 10 mg/L （24.4 and 24.0 d, respectively） compared with individuals reared in 20, 40, or 60 mg/L. Females reared in 5 mg/L lithium produced a mean of 16.5 neonates/brood and had the highest number of broods （3.0±1.95）. The rate of egg production （a）, the intrinsic rate of increase （rm）, net reproduction rate （R0）, and finite rate of increase （2） were highest for D. tibetana reared at 5 and 10 mg/L lithium, and the duration of development was shorter than for the remaining groups. The results indicated that rearing in 5 10 mg/L lithium can accelerate the growth and reproduction ofD. tibetana.

Layered farming for Marsupenaeus japonicus Bate

Marsupenaeusjaponicus Bate is one of the most valuable cultured shrimp species in China and outdoor earthen pond farming is the most common method of culturing this organism. The need to increase soil usage efficiency in aquaculture has been recognized and a great deal of research effort has been directed toward development of super-intensive farming systems. However, current research and development in this field is largely devoted to Litopenaeus vannamei Boone, while to M.japonicus Bate it has been neglected. In this study, a layered fanning system was designed and a 66-day study was conducted in M.japonicus Bate culture. The system comprised bracket and sand layers that divided a shrimp tank filled to a depth of 1.2 m into four water layers. Conventional tank culture （unlayered） was used as a control. The results show that survival rate, feed conversion efficiency and production of M.japonicus Bate in the layered farming system were 68%, 18%, and 0.59 kg/m^2, respectively, all of which are significantly higher than in the unlayered fanning system （P〈0.01）. These findings confirmed the possibility of using a layered system to culture M. japonicus Bate.

Effect of salinity on growth and first sexual maturity of Exopalaemon carinicauda(Holthuis, 1950)

To determine the optimal salinity for growth and first sexual maturity of ExopaIaemon carinicauda, the effects of salinity on growth and reproductive performance of early juvenile prawns of E. carinicauda were evaluated under laboratory conditions. Postlarvae from the same female broodstock were reared at six salinity levels （5, 10, 15, 20, 25, and 30） for 12 weeks. The specific growth rate （SGR） and survival rate （SR） under different salinity levels in the first 6 weeks were calculated and compared. SGR was significantly influenced by salinity. Prawns reared in salinity of 10 grew significantly faster （P〈0.05） than those reared in salinities of 5, 20, 25, and 30. However, ANOVA confirmed that there was no significant effect among the six salinity levels on SR. For the next 6 weeks, the body length （BL）, body weight （BW） at the first sexual maturity, and the age at median sexual maturity （As0） of females were measured and compared. Female prawns reared at salinity of 10 presented significantly shorter A50, but no significant differences among the six salinity levels for BL and BW at the first sexual maturity were observed. Based on the above information, the optimal salinity for growth and first sexual maturity of juvenile E. carinicauda is approximately 10.

Cricket Farming for Animal Protein as Profitable Business for Small Farmers in Indonesia

Cricket is widely recognized in Indonesia especially in Java island, and commonly kept by village farmers for food and feed. In general, crickets has very short life cycle （60-70 d）, with three weeks of laying period and egg production within the range of 200-1,500 eggs/female. The female has capability for multiple mating with several males and therefore produces more fertile eggs. Serial studies including experiments on laboratory and field observation of local crickets had been conducted to evaluate the farming practices and reproductive performance of three local species （Gryllus spp., Gryllus mitratus and Gryllus testaceus） which were given local feeds--Manihot esculenta and Carica papaya leaves. The experiment was conducted in randomized block design with feed as the treatments and species as the block. Cliring crickets （G. mitratus） fed with M. esculenta leaves revealed the highest total egg production （1,478.22 eggs）, with daily egg production of 32.85 eggs/d, the longest laying period （45 d）, the lowest feed intake （0.28 g/head） and feed conversion （0.93 mg/egg）, compared to Cendawang crickets （G. testaceus） and Gryllus spp.. The revenue and cost （R/C） ratio was 1.4, indicating that small scale cricket enterprise could offer significant profit and could be chosen as an alternative activities for earning regular income.

Factors that Affect Pellet Quality： A Review

Pelleting is the most popular thermal processing technique in poultry industry. Birds fed pelleted diets have greater feed intake and weight gain, and better feed conversion ratio. However, this better performance can only be achieved, if the pellets remain intact until they are ingested by the birds. Many factors may affect pellet physical quality, such as feed nutritional composition, ingredient particle size, conditioning temperature and time, feed moisture, etc.. Despite their importance, sometimes these factors are not managed properly, therefore, pelleted feed may not contain a high amount of intact pellets. In addition, the possible interactions among these variables may yield different responses in comparison with those expected when individual factors are considered. Very few experiments have been conducted to evaluate the impact of combined factors on pellet quality. This may be explained by the presence of many qualitative and quantitative factors in the manufacturing process. Research indicates that heat processing and feed formulation, especially fat inclusion level, are the factors which have the biggest influence on pellet quality. Strategies, such as the expansion process and fat inclusion restriction or post pellet liquid fat application could be implemented to produce high physical quality pellets. More research is needed to identify which factors have a positive or negative effect on pelleting process and to find new strategies to improve pellet physical quality.

The Main Causes of Calf Mortality in Dairy Farms in Poland

Calf mortality is one of important problems of calf rearing in dairy farms worldwide. Besides, several noninfectious factors, such as management around birth, colostrum management, calf housing, feeding system, hygiene and pathogens, play an important role in calf rearing. The aim of the study was to show the most common causes of mortality of calves up to 90 d of their lives. Some data are available concering calf rearing management on small and medium size dairy farm typical for Polish regions. The research was conducted in seven selected herds of Polish Holstein-Friesian cows located in South of Poland. Data on calves mortality covered the period of three years from 2004 to 2007 and were collected using medical documentation and medical inquire in the farms. All evidence was enrolled untill three months of age of calves. There were 1,800 calves tested. The influence of such factors as maintaining system （free stalls barn and stalls barns）, feeding systems and herd size on falls of calves was examined. Overall, mortality throughout the three months of study period was diarrhea, which increased the risk of death among calves younger than 90 d of age. Also, respiratory system disorders were the common cause of loss of calves. The calf mortality rate during 90 d in all herds registered in free stall barns was 61% and in stalls barns was only 29%. Effect of pneumonia in free stall barns was 18% and in stall barns was 29%. In all groups, calf mortality rates increased with increasing herd size.

The Effect of Stocking Density on the Behaviour and Welfare Indexes of Broiler Chickens

The effect of three stocking densities, ranging from 30 to 44 kg product per m2 on the performance, behaviour and welfare indexes in broiler chicken was investigated. Scan sampling for comparative behavior in all groups was carried out at 2 min intervals during 2-20 min periods for five days each week. It was found that the most common behaviour in all densities was lying （resting）, lying and standing behaviour was tended to increase in H than L group of all experimental period. Pecking behaviour was not constantly changed by stocking density. Locomotion was not only reduced with increasing age but increase stocking density of all experimental period and all groups. Body weight gain and feed efficient were, tend to increase in L than H group of 2 to 3 weeks ages, higher in L than H group （P 〈 0.05） of 4 to 5 weeks ages and all experimental period. Other behaviours （dustbathing, preening, eating or drinking） were not influenced （P 〉 0.05） by stocking density. It seems that gait, foot pad and hock burn score were improved in L than H group of 35 days age （P 〈 0.05）. The claw length of 21 days age was not affected by stocking density, but it was significantly different by stocking density of 35 days age （P 〈 0.05）. The duration of tonic immobility （TI-reaction） was tended to decreased age of 21 than 35 days, but not effected by stocking density. These data indicate that stocking density can influence broiler behaviour and welfare indexes.

Growth Profile of Gilthead Bream Reared in Mega Flow Re-circulating Aquaculture System

This study was designed to compare the effect of two exchange rates （ERs; 0.5 m^3 feed/kg and 1.5 m^3 feed/kg） in re-circulating aquaculture systems （RAS） on water quality and fish growth profiles on fish stocks （200 indiv/m^3 of 251.4 g e 20.67 g） of gilthead bream, Sparus aurata. Water quality, fish growth, specific growth rate （SGR） and feed conversion ratio under the two ERs were examined for a period of six months. Inorganic nutrient in RAS, temperature, dissolved oxygen and pH were measured daily. Feeding regime effect was also determined on the fish quality and organoleptic characteristics and thus opts to energy optimization of the system. The fish reared under the 1.5 m^3 feed/kg ER demonstrate enhanced growth, the daily SGR and the conversion ratio. Sensory test analysis revealed differences in the organoleptic characteristics between the two experimental fish stocks with considerably high acceptance scores for fish reared at high ER. Nutrient concentrations： ammonia, nitrate, nitrite and phosphate were lower in RAS of the highest ER when compared to those reared under the 0.5 m3/kg feed. Results suggest an ER of 1.5 m^3 feed/kg improved both fish quality and growth profile of the gilthead bream.

Probabilistic Chain Teleportation of a Qutrit-State

We investigate chain teleportation of a qutrit-state via the non-maximally two-qutrit entangled channels.For the case of four parties,the efficiencies of two chain teleportation protocols,the separate chain teleportation protocol(SCTP),and the global chain teleportation protocol (GCTP),are calculated.In SCTP the errors are corrected betweenevery step while in GCTP the errors are corrected only at the end.Furthermore,we present a piecewise global chainteleportation protocol (PGCTP) for keeping away from the inconvenience of error-correction of GCTP.We show thatPGCTP is more efficient than SCTP.

Effects of feeding and stocking density on digestion of cultured Atlantic salmon Salmo salar L.

The combined effects of feeding rate(0.8%,1.0%,and 1.2%initial body weight/day),feeding frequency(two,three,and four times/day) and stocking density(10,15,and 20 kg/m3) in recirculating aquaculture systems(RAS) on growth performance,digestion and waste generation of Atlantic salmon(Salmo salar L.) were investigated in an 8-week orthogonal experiment(L9(3)3) with a constant daily water renewal at 7.50%of total volume.No mortality occurred during the experimental period.Feed conversion ratio(FCR) varied from 0.90 to 1.13 and specific growth rate(SGR) ranged from 0.48%to 0.69%/day.SGR,thermal growth coefficient(TGC) and FCR were not significantly(P>0.05) affected by the three factors,while net protein utilization(NPU) was significantly(P<0.05) affected.Apparent digestibility coefficients(ADC) of dry matter in the present study were in the range 66.12%-73.55%.ADC in protein,lipid and energy were statistically different among all treatments and in the range of 90.07%-93.67%,81.54%-89.15%,and67.55%-71.87%,respectively.The proportion of mean total ammonia nitrogen excreted ranged from 1.37%to 1.64%of feed nitrogen at steady state,and the concentration of nitrogenous and phosphorus compounds were differently correlated to the three factors.The results will provide valuable reference data for culture management decisions in the Atlantic salmon farming industry.

Effect of Concentrate to Roughage Ratio on Cost Effective Growth Performance of Brahman Crossbred Calves

An experiment was conducted to evaluate the growth performance and cost per gain of Brahman × local crossbred bull calves receiving three diets with varying concentrate to roughage ratio （C：R） of 75：25, 65：35 and 55：45 on dry matter （DM） basis. Twelve bull calves （aging 11.5 ±1.2 months and 170.8 ± 13.0 kg live weight） divided into three equal groups were fed on three diets. The diets were balanced to 14.5% crude protein （CP） level and 10.5 MJ metabolizable energy （ME） per kg DM, formulating different concentrate mixtures. German grass （Echinoclora grousgali） and paddy straw were offered at 2：1 ratio on DM basis as roughages. The results revealed that C：R ratio did not affect （P 〉 0.05） the intake of feed and nutrients, feed efficiency （7.04, 6.94 and 6.76） and average daily gain （981,958 and 976 g）. Digestibility of nutrients was not affected （P 〉 0.05） by C：R. Animals fed diet with C：R = 55：45 had the lowest feed cost （Bangladeshi Taka 136.8 BDT/kg live weight gain）, which was increased （147.5 B DT and 153.8 BDT） non-significantly （P 〉 0.05） with the increasing level of concentrate. The diet consisting of 55% concentrate mixture showed similar results with the diet consisting of 75% concentrate mixture, but was comparatively economic. Therefore, considering the growth performance and cost per kg gain of Brahman crossbred growing calves, it may be concluded that the diet consisting of 55：45 C：R may be used for economic beef production.

湖南省农村居民狂犬病暴露处置现况调查

目的了解农村居民狂犬病暴露处置现况,探讨狂犬病高发影响因素,为制定有针对性的干预措施提供依据。方法采用多阶段抽样方法,对4个县40个村的部分居民户进行人户调查,对调查结果进行描述性流行病学分析。结果农村居民户犬、猫饲养率为38.68%,均以放养为主,犬密度为8.97只/100人,其兽用狂犬病疫苗免疫率为31.87%;农村居民年平均暴露率为2.22%,以家养犬、猫,年龄<15岁,学生的暴露率较高,暴露特征以到有犬、猫居民家中串门、被犬伤下肢、Ⅲ级暴露为多;暴露后仅28.23%立即自行处理伤口,部分还采用自敷草药等错误的处理方式,暴露对象有3/4就医,人平均处置费用416.68元,就诊对象中有4.30%拒绝使用狂犬病疫苗,Ⅲ级暴露者中有93.55%未使用狂犬病被动免疫制剂。结论农村居民为狂犬病暴露的高危人群,暴露主要来源于家犬;居民对狂犬病缺乏科学认识、经济条件有限是导致狂犬病暴露后处置不合规范要求的主要原因。

某药检所实验动物房空调通风节能设计探讨

本文结合深圳的某实际案例，具体分析了实验动物房中不同环境要求下暖风系统的设计要求，同时总结了本次设计中的技术难点，如何进行合理的通风系统设计，以及如何进行压力以及再热量控制。最后探讨了该案例中的热回收等节能措施，为今后动物房的设计提供了依据与参考。