Larval Gulf Coast ticks (Amblyomma maculatum) [Acari: Ixodidae] as host for Hepatozoon americanum [Apicomplexa: Adeleorina].

Laboratory-reared larval Gulf Coast ticks (GCTs) (Amblyomma maculatum) were exposed experimentally and found to acquire Hepatozoon americanum infection while feeding on parasitemic dogs. These ticks supported gamogonic and sporogonic development of the apicomplexan, and oocysts from newly molted nymphs were infectious for a dog. Other nymphs from this cohort that were allowed to feed on a blood-parasite naive sheep molted normally; the resulting adult ticks contained oocysts that were infectious for another dog. Merogonic development of H. americanum in the dogs and the resulting lesions/disease appeared similar, irrespective of whether infectious oocysts were derived from nymphal or adult ticks that acquired infection as larvae. In the system previously known, nymphal ticks acquire infection and adults harbor infective oocysts, which vertebrate hosts ingest. Given that larval A. maculatum can acquire infection and nymphs can harbor viable oocysts as demonstrated by this study, the potential variety of vertebrate hosts that can alternate with GCTs in maintaining an endemic cycle is considerably expanded.     

Sublethal infection of different pine species by the pinewood nematode

Bursaphelenchus xylophilus, the pinewood nematode and causal agent of pine wilt disease (PWD), is a globally destructive pine pest. PWD is favoured by high temperatures and drought, but B. xylophilus can also persist in symptomless hosts in areas not prone to PWD. We compared seedlings of different Pinus species that were inoculated with B. xylophilus when well-watered and under moderate temperatures, conditions that favour sublethal infections. We compared isolates of B. xylophilus in south-west Europe (Portugal) and south-east USA (Louisiana). P. pinea, P. pinaster, and P. radiata were challenged in both areas with inoculations of local B. xylophilus. P. sylvestris in Portugal and P. palustris in Louisiana were also tested. Seedling mortality was low, as expected, but nematode establishment was common. There were higher nematode densities and more damage in seedlings of P. sylvestris and P. radiata, followed by P. pinaster, with P. pinea and P. palustris proving to be more tolerant. Life history of hosts was a better predictor of resistance to B. xylophilus than geographical origin, even under sublethal conditions. Fast-growing species (P. radiata and P. pinaster) appeared most likely to be symptomless carriers in areas not prone to the development of PWD. Cold-adapted species (P. sylvestris) may still be suitable hosts for the pathogen, even at the sublethal conditions of their distribution areas. There were more nematodes per gram of host using nematode isolates from Portugal. Nonetheless, our results opposed the hypothesis that North American pinewood nematodes have such low virulence that they are obligatorily saprophytic.     

Tuna Red Meat as a Novel Ingredient in Pet Food for Dogs

ABSTRACT

Red meat from tuna canning factory was used to develop a pet food for dogs. Feed was developed by mixing cooked, dried, and powdered red meat with cereal flours in varying proportion. The combination that gave maximum hardness for the feed was selected as optimum. The developed feed had a crude protein content of 20.2 ± 0.95% and crude fat content of 4.70 ± 0.37%. Analysis of mineral content showed that it is rich in macro minerals, including phosphorus (2843.67 ± 206 ppm), sodium (1333.54 ± 56 ppm), and calcium (400.04 ± 21 ppm). Amino acid content of the feed showed that it meets the dietary requirements of dogs in terms of threonine, methionine, histidine, lysine, arginine, and tryptophan. Polyunsaturated fatty acid content of the feed was dominated by linoleic acid, followed by DHA and EPA.     

Physiological responses and HSP70 mRNA expression in GIFT tilapia juveniles,Oreochromis niloticus under short‐term crowding

Physiological responses and HSP70 mRNA expression to short‐term crowding were tested in juveniles genetically improved farmed tilapia (Oreochromis niloticus) (70.43 ± 4.43 g). Fish were kept at control group (5 g L^?1) and stress groups (low density 10 g L^?1, medium density 40 g L^?1 and high density 70 and 100 g L^?1) for 48 h. Each density was tested in triplicates. The effects of a short‐term exposure on the physiological responses of fish were determined before stress (0 h) and at 6, 12, 24 or 48 h post‐crowding. There was a significant increase in serum cortisol, total protein, lysozyme and aspartate aminotransferase (AST) activities in all stressed groups at 24 h post‐crowding (P < 0.05). Serum glucose and alanine aminotransferase (ALT) of 100 g L^?1 stressed group were lower than that of the control after 48 h of crowding stress (P < 0.05). The levels of serum triglyceride and cholesterol in crowding stress with high density were significantly decreased compared with the control group at 48 h. The mRNA expression data showed that hepatic HSP70 mRNA levels were markedly elevated at all stressed groups. HSP70 mRNA levels of 70 and 100 g L^?1 stressed groups decreased at 48 h compared with the 24 h post‐crowding. The protective ability of HSP70 was limited.     

Effect of Corn Moisture on the Properties of Pet Food Extrudates

Corn moisture (9.5–13.5%) was significantly correlated to extrudate properties, even though water was added at the extruder to compensate for the differences in moisture. Water addition was more effective at the preconditioner than at the extruder, and longer retention preconditioner improved expansion. Water added to the pet food formula apparently was absorbed by the other formula ingredients and not the corn. Controlling the specific mechanical energy did not compensate for differences in corn moisture.