Effects of early intermittent maternal separation on behavior, physiological, and growth performance in piglets.

In pig production, the management of piglets by batch lactation due to the increase in litter sizes of sows may result in intermittent early neonatal maternal separation (NMS). We speculated that NMS may affect the piglets cognitive growth performance and health. To determine the extent of the effect, 12 litters of crossbred piglets (Large White × Duroc × Min-pig) were used in this trial. Piglets in the control (Con) group (n = 6) were given a standard feeding method during lactation. Piglets in the experimental group (n = 6) were subjected to the NMS model, in which sows were led out of the enclosure with food every day (8:00-11:00 and 13:00-16:00) starting from postnatal day (PND) 7. During the separation, the piglets were supplemented with milk. All experimental piglets were weaned on PND 35. The piglets were observed for aggression, play, mutual sniffing, and exploratory behavior on PNDs 7, 8, 21, 22, 34, 35, 38, 39, 51, 52, 64, and 65. Physiological indicators, namely serum adrenaline, cortisol, interleukin (IL)-1ß, IL-4, IL-6, and tumor necrosis factor (TNF)-α were measured on PNDs 35, 38, and 65, while piglet growth performance was evaluated during suckling and 1 month after weaning. The results showed that aggressive behavior in the MS group was significantly higher than that in the Con group (P < 0.05). Playful and mutual sniffing behaviors in the MS group were significantly lower than those in the Con group except for PNDs 38 and 39 (P < 0.05). Active exploratory behavior in the MS group was significantly higher than that in the Con group on PNDs 7 and 8, and PNDs 21 and 22 (P < 0.05). The frequency of belly-nosing behavior was significantly higher in the MS group than that in the Con group except for PNDs 64 and 65 (P < 0.05). Compared with the Con group, epinephrine, IL-1ß, IL-6, and TNF-α concentrations on PNDs 35, 38, and 65 were significantly increased in the MS group (P < 0.01), while IL-4 concentration was significantly decreased (PND 35: P < 0.05; PNDs 38 and 65: P < 0.01). Compared with the Con group, the piglet diarrhea rate in the MS group during suckling was significantly increased (P < 0.01), the weaning weight was significantly decreased (P < 0.05), and it had no significant effect on the body weight at the end of the trial (P > 0.05). In conclusion, the early intermittent NMS created stress and affected the growth performance of piglets during suckling. However, the growth rate was improved by compensatory measures during late weaning.

Although management methods, such as split-suckling and foster care, in pig production can improve piglet survival rates, these methods inevitably lead to neonatal maternal separation which is an early stress on the body, and can have serious negative effects on the body. In this experiment, we investigated the effect level of neonatal maternal separation on behavior, physiology, and growth performance of piglets. The study found that early intermittent maternal separation leads to anxiety and behavioral changes in piglets, negatively affecting diarrhea rates and weaning weights in suckling piglets, but the effects on growth performance in lactating piglets can be ameliorated during the nursing period.

A simple multiple centrifugation method for large-area homogeneous perovskite CsPbBr3 films with optical lasing.

Large scale cesium lead-halide (CsPbX3, X = Cl, Br, and I) perovskite films have become the basis of laser applications. Common fabrication methods such as spin-coating and thermal evaporation have a trade-off between high quality and low cost. Herein, we reported a facile method for preparing a large area homogeneous perovskite CsPbBr3 film via a multiple centrifugal deposition and solvent annealing (MCDSA) method. This method is superior because it can control the thickness (180 nm to 880 nm) of the film, ensure the film is crack and pinhole free, has a large area (2.5 cm × 2.5 cm), and has a low surface roughness (a root mean square of 32 nm). Multiple times of centrifugation and solvent annealing in the MCDSA method are key to improving the quality of the film as well as the laser performance. With increased centrifugation cycles from one to four, the thickness of the film increases from 180 nm to 880 nm, leading to a decrease in the laser threshold from 18.1 µJ cm-2 to 14.2 µJ cm-2 and an increase in the gain coefficient from 78.5 cm-1 to 112.7 cm-1. When solvent annealing is employed, the gain coefficient is further increased to 122.7 cm-1.

Effects of confinement duration and parity on stereotypic behavioral and physiological responses of pregnant sows.

The aim of this study was to evaluate the effects of space restriction stress on the stereotypic behavioral and physiological responses of different parity sows, and it is necessary to understand such effects due to space restriction to improve the welfare of the sows in confined conditions. We selected fifty pregnant sows (Large White) at primiparity and first to fifth parity in a confined farm with the same body condition and due date (3±1.5days). Behavioral observations and physiological analysis were carried out during spatial confinement throughout pregnancy. The results showed that there were no significant changes in vacuum-chewing, bar-biting, trough-biting and the concentrations of serum IL-6 in primiparous sows during the initial confinement (0-8days). With the increase of the confinement duration, the serum cortisol, IgA, IL-6 concentrations and the vacuum-chewing frequency of sows in all groups increased significantly, and the serum concentrations of C-reactive protein and Pig-MAP increased significantly except for the sows in the first and second parity groups. The serum cortisol, IgA, IL-6 concentrations and the vacuum-chewing frequency of older sows were significantly higher than those of the young sows throughout the entire restricted feeding period, but the serum C-reactive protein concentrations of primiparous gilts was significantly higher than those of the other groups. The serum cortisol, IgA, IL-6 concentrations and bar-biting and trough-biting frequencies of all parity sows decreased significantly after entering the delivery bed. In conclusion, long-lasting and recurrent environmental constraints can significantly increase the frequency of stereotypical behavior and serious psychological and physical stress, seriously damaging sow welfare.