Parental behavior and anxiety in isogenic and outbred mice given access to two types of nesting materials

The objective was to investigate if providing two types of nesting materials could modulate parental behavior and anxiety in laboratory mice. For that, 54 full-sib BALB/cJ and 50 randomly mated Swiss Webster mouse pairs were employed in a completely randomized designwith a 2×2 factorial arrangement (two genetic groups and with/ without access to nesting materials). Eight pieces of disposable polypropylene caps/ hairnets and 3g of cotton were provided as nesting materials to half the cages from each genetic group. Maternal and paternal behaviors were recorded on the third reproductive cycle, twice a week, for three weeks, using scan sampling. The behaviors were recorded every 10s for a period of 10min (totaling 60 records) each day. Dams (N=40) were tested in the elevated plus maze (EPM) on the fifth reproductive cycle, 7–10 days postpartum. Their 21-days-old weanlings (N=208) were tested in the same apparatus. Total number of closed arm entries was used as measurement of motor activity, the percentage of time spent on open arms as measurement of anxiety and head dipping time as measurement of exploratory behavior. The provision of nesting materials increased the frequency of dams licking pups (1.72±0.20 vs. 1.10±0.21, P=0.0342) and of sires resting in contact with pups (25.0±1.5 vs. 18.9±1.5, P=0.0050), while simultaneously decreased the frequency of sires in non-contact rest with pups (6.4±1.1 vs. 10.8±1.2, P=0.0074). Swiss Webster dams were recorded nursing their pups in the arched-back posture more frequently than BALB/cJ dams (9.63±0.89 vs. 7.13±0.86, P=0.0187) and Swiss Webster sires showed a higher frequency of nest building than BALB/cJ sires (0.80±0.16 vs. 0.31±0.15, P=0.0281). Motor activity was higher (8.00±0.43 vs. 2.83±0.41, P<0.0001) and anxiety was lower (3.2±28.4 vs. 2.4±3.1%, P<0.0001) in Swiss Webster than in BALB/cJ dams. Anxiety (26.6±3.2 vs. 37.9±3.5%, P=0.0168) was also lower in Swiss Webster than in BALB/cJ weanlings. The availability of nesting materials increased the time dams spent in head dipping (10.9±2.0 vs. 4.6±1.9, P=0.0087), but weanling behaviors in the EPM were unaffected. Slight differences in parental behavior and contrasting patterns of anxiety and motor activity were found between genetic groups. The provision of nesting materials promoted an intensification of favorable parent-offspring interactions and enhanced exploratory behavior of dams.

Parental behavior and anxiety in isogenic and outbred mice given access to two types of nesting materials

The objective was to investigate if providing two types of nesting materials could modulate parental behavior and anxiety in laboratory mice. For that, 54 full-sib BALB/cJ and 50 randomly mated Swiss Webster mouse pairs were employed in a completely randomized designwith a 2×2 factorial arrangement (two genetic groups and with/ without access to nesting materials). Eight pieces of disposable polypropylene caps/ hairnets and 3g of cotton were provided as nesting materials to half the cages from each genetic group. Maternal and paternal behaviors were recorded on the third reproductive cycle, twice a week, for three weeks, using scan sampling. The behaviors were recorded every 10s for a period of 10min (totaling 60 records) each day. Dams (N=40) were tested in the elevated plus maze (EPM) on the fifth reproductive cycle, 7–10 days postpartum. Their 21-days-old weanlings (N=208) were tested in the same apparatus. Total number of closed arm entries was used as measurement of motor activity, the percentage of time spent on open arms as measurement of anxiety and head dipping time as measurement of exploratory behavior. The provision of nesting materials increased the frequency of dams licking pups (1.72±0.20 vs. 1.10±0.21, P=0.0342) and of sires resting in contact with pups (25.0±1.5 vs. 18.9±1.5, P=0.0050), while simultaneously decreased the frequency of sires in non-contact rest with pups (6.4±1.1 vs. 10.8±1.2, P=0.0074). Swiss Webster dams were recorded nursing their pups in the arched-back posture more frequently than BALB/cJ dams (9.63±0.89 vs. 7.13±0.86, P=0.0187) and Swiss Webster sires showed a higher frequency of nest building than BALB/cJ sires (0.80±0.16 vs. 0.31±0.15, P=0.0281). Motor activity was higher (8.00±0.43 vs. 2.83±0.41, P<0.0001) and anxiety was lower (3.2±28.4 vs. 2.4±3.1%, P<0.0001) in Swiss Webster than in BALB/cJ dams. Anxiety (26.6±3.2 vs. 37.9±3.5%, P=0.0168) was also lower in Swiss Webster than in BALB/cJ weanlings. The availability of nesting materials increased the time dams spent in head dipping (10.9±2.0 vs. 4.6±1.9, P=0.0087), but weanling behaviors in the EPM were unaffected. Slight differences in parental behavior and contrasting patterns of anxiety and motor activity were found between genetic groups. The provision of nesting materials promoted an intensification of favorable parent-offspring interactions and enhanced exploratory behavior of dams.

Changes in renal gene expression associated with induced ochratoxicosis in chickens: activation and deactivation of transcripts after varying durations of exposure.

Exposure to ochratoxin A (OTA) can lead to changes in global gene expression. This study investigated the individual expression of genes turned on and off in renal cells of chicks after different durations of exposure to dietary OTA. One hundred and eighty day-old male broiler chicks (Ross 308) were randomly assigned to a 3 × 3 factorial arrangement of treatments (3 levels of OTA: 0, 1 and 2 mg OTA/kg diet and 3 time periods: 7, 14 and 21 d). Birds were allocated to 36 pens (4 replicate pens of 5 birds each per treatment). For RNA-Sequencing analysis (RNA-Seq), kidney samples were collected weekly from 3 controls and 3 chicks fed 1 mg OTA/kg. Birds fed 2 mg OTA/kg diet were not chosen for analysis because their reduced feed intake could affect gene expression. The libraries were constructed by Illumina's TruSeq RNA protocol. NextGENe software was used for alignment and transcript quantification. Reads per kilobase of target per million tiled reads (RPKM) were used in the Binary test analysis (P < 0.05). The highest RPKM values were used as criterion for the selection of the genes described. A total of 27,638,976 50-bp RNA-Seq reads were produced over the 3 time periods. Transcripts (40,782) were assembled de novo and annotated by homology to either G. gallus or H. sapiens. The genes activated at 7 d were IL9 and TULP1, at 14 d was GHSR and at 21 d were GRK6 and GAPDH. Unlike all other genes, LOC396365 was activated during all time periods. In contrast, the genes deactivated at 7 d were SPAG4 and LOC100857131, at 14 d were LOC771469, NKX2-1, NKX2-8, FOXO1, MyHC and CLDN18 and at 21 d was XPC. The B-G gene was turned off at 7 and 21 d. All of these genes were involved in kidney toxicity. Therefore, the turning on and off responses of these genes may contribute to carcinogenic and tumorigenic effects of OTA in birds.

Lifetime reproductive efficiency of BALB/c mouse pairs after an environmental modification at 3 mating ages.

The aim of this study was to evaluate the effects of an environment change and the age at which mating pairs were formed on the lifetime reproductive performance of BALB/c mice. We assigned 60 monogamous pairs to a randomized design in a 2 × 3 factorial arrangement (with or without an environmental modification and with 3 mating ages: 28, 45, or 60 d). Autoclaved cardboard tubes (length, 10 cm; diameter, 4 cm) were used as the environmental modification. Data were collected from a total of 456 litters over a period of 10 mo. The mice tore the cardboard tube and used its parts both as shelters and as nesting material. The presence of a cardboard tube decreased the preweaning litter mortality rate in the first 6 reproductive cycles. Mating at 28 or 45 d of age also decreased the preweaning mortality rate in the first 6 reproductive cycles, compared with monogamous pairs formed at 60 d of age. Treatments did not affect age at first parturition, number of litters, time between litters, or litter size and weight at birth and weaning. In addition to contributing to animal wellbeing, providing a cardboard tube improved productivity by decreasing the preweaning mortality rate. BALB/c siblings should be paired for mating when no older than 28 d, to reduce preweaning mortality of the offspring.

Association of IGF1 and KDM5A polymorphisms with performance, fatness and carcass traits in chickens.

Two functional and positional candidate genes were selected in a region of chicken chromosome 1 (GGA1), based on their biological roles, and also where several quantitative trait loci (QTL) have been mapped and associated with performance, fatness and carcass traits in chickens. The insulin-like growth factor 1 (IGF1) gene has been associated with several physiological functions related to growth. The lysine (K)-specific demethylase 5A (KDM5A) gene participates in the epigenetic regulation of genes involved with the cell cycle. Our objective was to find associations of selected single-nucleotide polymorphisms (SNPs) in these genes with performance, fatness and carcass traits in 165 F(2) chickens from a resource population. In the IGF1 gene, 17 SNPs were detected, and in the KDM5A gene, nine SNPs were detected. IGF1 SNP c.47673G > A was associated with body weight and haematocrit percentage, and also with feed intake and percentages of abdominal fat and gizzard genotype × sex interactions. KDM5A SNP c.34208C > T genotype × sex interaction affected body weight, feed intake, percentages of abdominal fat (p = 0.0001), carcass, gizzard and haematocrit. A strong association of the diplotype × sex interaction (p < 0.0001) with abdominal fat was observed, and also associations with body weight, feed intake, percentages of carcass, drums and thighs, gizzard and haematocrit. Our findings suggest that the KDM5A gene might play an important role in the abdominal fat deposition in chickens. The IGF1 and KDM5A genes are strong candidates to explain the QTL mapped in this region of GGA1.