Immunization of young chickens by trickle infection with Eimeria tenella.

Immunization of chickens was attempted with low levels of Eimeria tenella oocysts (50 oocysts per day) over the first 1 or 2 weeks of life--the "trickle infection" (TI) method. When chickens were immunized by TI at 0-13 days of age, no cecal lesions and a reduced number of oocysts in ceca were observed after challenge at 17 days of age. TI at 0-6 days of age conferred better protection against challenge with E. tenella than did TI at 7-13 days. However, cecal lesions were observed in almost all of these chickens. These findings indicated that TI for 2 weeks (0-13 days of age) provided better immunity than TI for 1 week (0-6 or 7-13 days of age).     

Avian infectious bronchitis virus: a possible cause of reduced fertility in the rooster

The formation of epididymal stones in the rooster epididymis is a widespread problem that has detrimental effects on sperm production and fertility. The cause of epididymal stones is unknown, but an infectious agent, the avian infectious bronchitis virus (AIBV), has been implicated. The goal of this study was to determine if administering the live attenuated AIBV vaccine to male chicks increases the incidence of stones in the epididymal region of the adult rooster. Specific pathogen free (SPF) Leghorn roosters were divided into two groups: a vaccine-free group (n = 7) and a group vaccinated with AIBV (n = 12). The vaccine was administered orally at 2, 4, 10, and 14 wk of age. Blood was drawn weekly to monitor antibodies to AIBV. At 26 wk of age, blood was obtained to determine testosterone concentrations, and reproductive tracts were removed to analyze daily sperm production and to detect epididymal stones. Nine of 12 vaccinated roosters developed stones, whereas those not given the vaccine did not develop stones. Serum testosterone concentrations were significantly (P < 0.05) reduced in vaccinated roosters with epididymal stones (3.6 +/- 0.30 ng/ml) when compared with nonvaccinated roosters that did not have epididymal stones (7.0 +/- 1.63 ng/ml). Testis weight was significantly (P < 0.05) reduced in vaccinated roosters with epididymal stones (12.1 +/- 0.76 g), as compared with nonvaccinated roosters without epididymal stones (15.2 +/- 0.81 g). Daily sperm production was significantly (P < 0.05) decreased in vaccinated roosters with epididymal stones (5.03 +/- 0.31 x 10(8) sperm/testis/day) when compared with nonvaccinated roosters without epididymal stones (7.43 +/- 0.52 x 10(8) sperm/testis/day). Comparing daily sperm production on a per gram basis, vaccinated roosters with epididymal stones had 4.38 +/- 0.14 x 10(7) sperm/g of testis, which was significantly (P < 0.05) smaller than nonvaccinated roosters without epididymal stones, which had 5.17 +/- 0.17 x 10(7) sperm/g of testis. We conclude that the use of a live attenuated AIBV vaccine increases the incidence of epididymal stones in roosters, resulting in decreased sperm production and decreased serum testosterone concentrations.     

Pattern similarity analysis of amino acid sequences for peptide emulsification

A new computer program for homology similarity search (HSS) was introduced. Application of the HSS to peptide sequences of short peptides with fewer 32 amino acid residues has explained the underlying mechanism of their emulsifying ability. It was found that certain regularity in the frequency of alternate polar/apolar cycle with high hydrophobic similarity density was required to obtain good emulsion. To supplement this required regularity, charge distribution, molecular flexibility, and a structural torsion caused by a proline residue might also play roles.     

Decision-making on the use of diverse combinations of agricultural products and natural plants in pig feed: a case study of native pig smallholder in northern Thailand

We have identified the feed offered to native pigs in a case study of smallholder in northern Thailand. We examined the types and fresh weights of pig feed over two 10-day periods in household A, in September 2006 (rainy season) and in December 2006 and January 2007 (dry season). The study results are as follows. (1) They offered 18 types of feed in total during the rainy and dry seasons, of which seven types were common to the rainy and dry seasons, five types were offered during the rainy season only, and six types during the dry season only. (2) They offered agricultural products as 34% of feed (rainy season) and 61% of feed (dry season), and natural plants used exclusively for pig feed as 66% of feed (rainy season) and 39% of feed (dry season). (3) The feed combinations at each feeding time differed 80% of the time during both the rainy and dry seasons. These results show not only that they offered diverse combinations of agricultural products and natural plants as pig feed, but also that they changed feed kinds in both the rainy and dry seasons.     

Reproductive performance analysis of native pig smallholders in the hillside of northern Thailand

We described the reproductive performance of native pigs raised by smallholders in a traditional way and used for ritual sacrifice in a Hmong village in the hills of northern Thailand. Field study was conducted between May 2005 and January 2007 (13 months in total). The pig reproductive performance in ten households during two years (January 2005 to December 2006) was as follows: The 15 farrowing samples in the households had an average litter size at birth of 7.1 and litter size at weaning of 6.0 (pre-weaning mortality 16%). A total of 107 piglets were born in the ten households during the two years, an average of 5.4 piglets per household per year. We were only able to collect data on farrowing intervals in three cases, two of eight months and one of 19 months. There was no concentrated farrowing period: of the 15 farrowings, there were seven months with one farrowing each (February, April, May, June, July, September, November), four with two farrowings (January, March, August, December), and one with none (October). This indicates that households have a variety of attitudes to pig reproduction, and that there is no seasonality in farrowing.     

Puerperal and parental experiences alter rat preferences for pup odors via changes in the oxytocin system

In the rat, induction of maternal behavior depends on the parity of the female. For example, nulliparous (NP) females need longer exposure to pups than multiparous (MP) or lactating (L) females to exhibit similar maternal behavior. In this study, we investigated the role of brain oxytocin in the approaching behavior of these female rats. Olfactory preferences for pup odors were examined for 8 consecutive days. Each preference test was followed by direct overnight exposure to pups. On the 8th day, MP and L, but not NP females showed robust pup-odor preferences. After the behavioral test, half of the females were exposed to pups for 2 h, whereas the other half were not. The females were then sacrificed to analyze brain oxytocin (OXT) and vasopressin (AVP) activities by cFos immunohistochemistry and to quantify their receptor mRNA expression using real-time PCR. In the paraventricular nucleus (PVN), the percentage of cFos-positive OXT neurons was significantly larger in MP and L females than in NP females after pup exposure. No significant differences were found in cFos expression in OXT neurons of the supraoptic nucleus (SON) or in AVP neurons of either the PVN or SON. Expression of OXT receptor mRNA in the medial preoptic area and amygdala of the control groups was also higher in MP females than in NP females. Finally, we demonstrated that infusion of OXT into the lateral ventricle of NP females promoted preferences for pup odors. These results indicate that puerperal and parental experiences enhance the responsiveness of OXT neurons in the PVN to pup stimuli and establish olfactory preferences for these odors in a parity-dependent manner.     

FT-Raman spectroscopy, fluorescent probe, and solvent accessibility study of egg and milk proteins

Due to possible contribution of both electrostatic and hydrophobic interactions, use of anionic fluorescent probes such as 1-anilinonaphthalene-8-sulfonic acid (ANS) and cis-parinaric acid (CPA) for the measurement of protein surface hydrophobicity (S0) has been controversial. A neutral probe, 6-propionyl-2-(dimethylamino)-naphthalene (PRODAN), may circumvent this problem. To select the best indicator of S0, in this study, the data for nine model proteins in phosphate buffer, pH 7.5, measured using the above-mentioned probes, was compared to their FT-Raman spectra and calculated solvent accessibility values. Log S0 measured using CPA had the highest correlation (r = 0.874) with the intensities of Raman spectral signals at 760 cm(-1) and 2800-3100 cm(-1), which were combined using a mixture design based on the random-centroid optimization. The order of correlation of Raman spectral parameters with S0 values were CPA > PRODAN > ANS. FT-Raman spectroscopy, therefore, identified CPA, followed by PRODAN, as the fluorescent probe of choice for describing surface hydrophobicity. However, the amino acid surface accessibility calculated using the PredictProtein software was not useful in identifying the best fluorescent probe for the measurement of S0.     

Effects of feeding high volumes of milk replacer on reproductive performance and on concentrations of metabolites and hormones in blood of Japanese black heifer calves

We evaluated the effects of feeding high volumes of milk replacer on growth and reproductive performances in Japanese black heifers. Fifty-one heifers were fed milk replacer at 9 L/day for 60 days (9 L × 60 days; n = 18) or 41 days (9 L × 41 days; n = 15), or at 7 L/day for 40 days (7 L × 40 days; n = 18). Artificial insemination (AI) was performed on heifers with ≥270 kg body weight and ≥116 cm body height at 300 days of age. The age at the first AI was 0.35 month later for 7 L × 40 days than the other groups (p < .01). However, age at calving did not differ among treatments (22.1 months). The interval from the first AI to pregnancy tended to be ~2 months longer for the 9 L × 60 days than the other groups (p = .07). Our results showed that feeding high volumes of milk replacer may reduce the age at calving via an improved rate of growth. In addition, we propose that feeding a maximum of 7 L milk replacer for 40 days may be the most appropriate rearing regime because the success of pregnancy per AI may be reduced in calves fed a maximum of 9 L for 41 and 60 days.