Effects of fat type and emulsifier in feed on growth performance, slaughter traits, and lipid metabolism of Cherry Valley ducks

A 2-factor test design was used to investigate the effect of an emulsifier (Aldo®, Lonza, America) (200 g/t) in the diet of Cherry Valley meat ducks to replace some of 2 different oils (animal fat and vegetable oil) on meat production performance, slaughter traits, and fat metabolism. The 900 healthy 18-day-old ducks were grouped into 6 treatments, each with 5 replicates and 30 meat ducks per replicate. The 2 fat sources were established as a positive control group, a negative control group (positive control group-some oil (equivalent to metabolic energy of 50 kcal/ton)), and an emulsifier group (negative control group + 200 g/ton Aldo). The results showed that addition of different fat sources in feed had no significant effect on growth performance, carcass properties, and fat metabolism of 18- to 42-day-old meat ducks (P > 0.05). Reducing the amount of oil used in the feed lowered the growth performance, carcass properties, and affected fat metabolism of meat ducks. However, in feeds with 2 fat sources, some oils were replaced by adding Aldo without affecting growth performance and carcass properties of meat ducks, and improved their fat metabolism, reduced triglycerides (TG) in serum, and increased activity of lipoprotein and hepatic lipases in liver and of pancreatic lipase. Thus, addition of Aldo to a low fat diet could improve growth performance, carcass quality, and lipid metabolism, and promote digestion and absorption of fat for meat ducks.

Fowl adenovirus serotype 4: Epidemiology, pathogenesis, diagnostic detection, and vaccine strategies

Fowl adenovirus (FAdV) serotype-4 is highly pathogenic for chickens, especially for broilers aged 3 to 5 wk, and it has emerged as one of the foremost causes of economic losses to the poultry industry in the last 30 years. The liver is a major target organ of FAdV-4 infections, and virus-infected chickens usually show symptoms of hydropericardium syndrome. The virus is very contagious, and it is spread both vertically and horizontally. It can be isolated from infected liver homogenates and detected by several laboratory diagnostic methods (including an agar gel immunodiffusion test, indirect immunofluorescence assays, counterimmunoelectrophoresis, enzyme-linked immunosorbent assays, restriction endonuclease analyses, polymerase chain reaction (PCR), real-time PCR, and high-resolution melting-curve analyses). Although inactivated vaccines have been deployed widely to control the disease, attenuated live vaccines and subunit vaccines also have been developed, and they are more attractive vaccine candidates. This article provides a comprehensive review of FAdV-4, including its epidemiology, pathogenesis, diagnostic detection, and vaccine strategies.

Breed-specific transcriptome response of spleen from six to eight week old piglet after infection with Streptococcus suis type 2

Different pig breeds have shown differential susceptibility to the pathogen infection; however, molecular mechanisms of the infection susceptibility are not fully understood. Streptococcus suis type 2 (SS2) is an important zoonotic pathogen. To identify the genes responsible for infection susceptibility, pigs from two different breeds (Enshi black and Landrace) were inoculated with SS2 and their spleen transcriptome profiles were investigated in the present study. The differentially expressed genes (DEGs) were analyzed from infected versus control pigs in each breed, and then compared between both pig breeds. Enshi black pig showed more DEGs than Landrace (830 vs. 611) and most of these were due to down-regulated genes (543 vs. 387). However some DEGs were uniquely expressed in one breed, some were expressed in opposite direction in both breeds. A number of candidate genes and pathways are identified which might be involved in susceptibility to SS2, for example, MMP9 and Resistin were only significantly expressed in Landrace. NPG3 and PMAP23 were up-regulated in Landrace whereas down-regulated in Enshi black. LENG8 in control Landrace have inherently higher expression than control Enshi black. IGKV6 is down-regulated in Landrace but up-regulated in Enshi black. Overall, the transcriptome profiles are consistent with the clinical signs, i.e. the Enshi black is more susceptible to SS2 infection than Landrace. This is the first study to identify differential gene expression between indigenous and modern commercial pigs after in vivo SS2 infection using RNA-seq. The significant DEGs in splenic profiles between two pig breeds suggested considerable involvement of genetic background in susceptibility to the SS2 infection in pigs.