Optimizing growth and antioxidant function in heat-stressed broilers with vitamin C and betaine supplementation.

This study investigates the potential of vitamin C (VC) and/or betaine (Bet) to enhance growth performance, regulate serum metabolism, and bolster antioxidant function aiming to mitigate the impact of heat stress (HS) on broilers. Two hundred Ross 308 broilers at 28 days of age were randomly assigned to five groups. The control group, housed at 24 ± 1℃, was fed a basal diet. High-temperature treatment groups, housed at 32 ± 1℃, received a basal diet with 0 (HS group), 250 mg/kg VC (HSVC group), 1000 mg/kg Bet (HSBe group), and 250 mg/kg VC + 1000 mg/kg Bet (HSVCBe group). On day 42, assessments were made on growth performance, muscle quality, serum biochemistry, and antioxidant function. Results revealed that HS significantly lowered (P < 0.05) average daily feed intake (ADFI), the degree of redness (a*) in muscles, and serum total superoxide dismutase (T-SOD) level. It also reduced (P < 0.01) average daily gain (ADG), and serum total antioxidant capacity (T-AOC) level, while increasing (P < 0.05) shear force, serum direct bilirubin (D-BIL), uric acid (UA), and malondialdehyde (MDA) levels compared with the control group. Dietary supplementation of VC and Bet, either alone or in combination, significantly decreased shear force and serum UA level, while increasing ADG and serum T-AOC, T-SOD level compared with the HS group (P < 0.05). In conclusion, the addition of VC and/or Bet to the diet proves effective in enhancing the growth performance of HS-exposed broilers through the positive regulation of serum chemical metabolism and the alleviation of oxidative damage.

Response of growth performance and cecum microbial community to cyclic heat stress in broilers.

Heat stress (HS) can affect growth performance through alterations in specific gut microbiota, which greatly threatens poultry production. How HS affects the mechanisms of microbial changes in the poultry cecum and the complex interactions between cecal microbial changes and growth performance have not yet been well evaluated. This study was conducted to examine the changes in growth performance and cecal microbiotal community in cyclic heat stress (CHS)-treated broilers. A total of 200 twenty-eight-day-old female Arbor Acres (AA) broilers were equally allotted into neutral ambient temperature group (TN group, 24 ± 1°C, 24 h/day) and CHS group (33 ± 1°C, 8 h/day) with five replicates of 10 broilers each, respectively. Growth performance, cecum microbial diversity, flora composition, and community structure were analyzed on days 35 and 42. The decreased average daily feed intake (ADFI), average daily gain (ADG), and the increased feed/gain ratio (F:G) were observed in heat-stressed broilers on days 35 and 42. The alpha and beta diversity index had no significant changes at the two experimental periods (P > 0.05). At the genus level, CHS significantly increased the relative abundance of Enterococcus at 42 days (P < 0.05). Based on the analysis of linear effect size feature selection, CHS made an enriched Reyranella and a reduced Romboutsia and Ruminiclostridium at 35 days of age (P < 0.05). CHS made an enriched Weissella and Enterococcus at 42 days of age (P < 0.05). The present study revealed that CHS reduces broiler growth performance and alters the microbial community of the cecum microbiota and the abundance of species. These findings are of critical importance to alleviate the negative effects of CHS on broiler chickens' growth performance by maintaining gut microbial balance.

Cyantraniliprole seed treatment effectively controls wireworms (Pleonomus canaliculatus Faldermann) and white grubs (Anomala corpulenta Motschulsky) in maize fields.

Wireworms and white grubs are destructive underground pests in maize fields in China. Cyantraniliprole has good control effect on coleoptera pests. Here, we evaluated the toxicity of cyantraniliprole to the second instar larvae of Anomala corpulenta Motschulsky and third-instar of larvae of Pleonomus canaliculatus Faldermann and the effects of sublethal concentrations on the activity of antioxidant and detoxification enzymes. We also explored the efficacy of cyantraniliprole on underground pests under indoor and field conditions. The LC50 of cyantraniliprole for the third instar larvae of P. canaliculatus was 23.3712 mg/L, and that for the second instar larvae of A. corpulenta was 5.9715 mg/L. Cyantraniliprole can activate the activity of superoxide dismutase (SOD), peroxidase (POD), and glutathione S-transferase (GST) to different degrees at a sublethal dose. According to the pot experiment and the control efficacy test in the field, the indoor control effect of cyantraniliprole seed treatment on P. canaliculatus and white grubs was approximately 80%, and the maximum increase in yield achieved through cyantraniliprole application was approximately 15% in the field efficacy test. Cyantraniliprole has a strong control effect on wireworms and white grubs, so it can be used to treat seeds to control underground pests in maize fields.

Effect of dietary supplemental vitamin C and betaine on the growth performance, humoral immunity, immune organ index, and antioxidant status of broilers under heat stress.

Heat stress (HS) has become one of the important factors affecting the development of animal husbandry. The purpose of this experiment was to investigate whether vitamin C (Vc) and betaine (Bet) improve immune organ index and humoral immunity by enhancing the antioxidant status of immune organs, thus protecting broilers from HS-induced injuries. A total of 200 28-day-old Ross 308 broilers were randomly assigned into 5 groups (n = 4 replicates/group, 10 broilers/replicate) which were reared at different ambient temperatures (24 ± 1°C or 33 ± 1°C). The control group fed basal diet, while high-temperature groups were either fed a basal diet (HS group) or a basal diet supplemented with 250-mg Vc/kg diet (HSVc group), 1000-mg Bet/kg diet (HSBet group), and 250-mg Vc plus 1000 mg Bet/kg diet (HSVcBet group), respectively. On day 42, growth performance, humoral immune function, immune organ index, and antioxidant capacity were measured. HS reduced the productive performance of broilers, antibody potency against the Newcastle disease virus (NDV) and sheep red blood cells (SRBC), indices of thymus and bursa, and antioxidant capacity of immune organs. Adding Vc alone or in combination with Bet improved performance, NDV and SRBC antibody potency, thymus and bursa indices, and antioxidant capacity of immune organs in heat-stressed broilers, with the most effective being combination. In summary, HS reduces the antioxidant capacity and immune organ development status of broiler immune organs. Vc and/or Bet can improve the development of immune organs and restore part of the production performance by regulating the antioxidant status of immune organs, among which the combined addition of Vc and Bet has the best effect.

Effects of betaine on viability, apoptosis, function protein expression and oxidative status in heat-stressed IEC-6 cells.

Intestinal epithelial dysfunction is one of the key factors in the pathogenesis of heat stress-induced disease. The purpose of this experiment was to investigate whether betaine protects IEC-6 cells from dysfunction induced by heat stress (HS) through antioxidative mechanism. The IEC-6 cells were divided into four groups: control group incubated at 37 °C, while those in heat treated groups (41 °C for 24 h) were pretreated with 0, 0.5 and 1 mmol/L betaine, respectively. Cell viability, apoptosis, barrier function protein and oxidative status were analyzed. Compared to control group, the rate of apoptosis and the Bax and caspase-3 expressions significantly increased in HS group (P < 0.05), however, cell activity, total antioxidative capacity (T-AOC), activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and the expression of Bcl-2, claudin-1 and occludin decreased significantly (P < 0.05). Betaine (0.5 mmol/L) can significantly enhance IEC-6 cell viability, while significantly reduce the apoptosis rate of cell during HS (P < 0.05). Meanwhile, the expression of Bcl-2, claudin-1 and occludin proteins were also significantly upregulated (P < 0.05) when compared to HS group. HS had a negative impact on IEC-6 cells, while betaine protected from damage caused by HS via increasing the antioxidative capacity. This suggested that betaine might be an effective dietary additive to protect animals from detrimental intestinal reactions caused by HS.

Effects of thifluzamide on soil fungal microbial ecology.

Thifluzamide, a succinate dehydrogenase inhibitor fungicide, has been used extensively for many diseases control and has the risk of accumulation in soil ecology. In order to study the ecotoxicity of thifluzamide to soil fungal communities, typical corn field soils in north (Tai'an) and south (Guoyang) China were treated with thifluzamide (0, 0.1, 1.0 and 10.0 mg/kg) and incubated for 60 days. Thifluzamide exposure promoted soil basal respiration, and significantly reduced the number of soil culturable fungi and the abundance of soil fungi (RT-qPCR) in middle and late treatment period (15, 30, 60 days). Illumina Mi-Seq sequencing revealed that thifluzamide could reduce fungal alpha diversity (Sobs, Shannon, Simpson indexes) and change fungal community structure. FUN Guild analysis showed that the relative abundance of Undefined Saprotroph increased after the thifluzamide treatment, whereas that of Plant Pathogen decreased, and we concluded that exposure to thifluzamide could change the function of soil fungi. This study evaluated the soil ecological risk caused by thifluzamide's release into soil, providing a basis for its rational application.

Effects of the novel HPPD-inhibitor herbicide QYM201 on enzyme activity and microorganisms, and its degradation in soil.

QYM201 is a 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibiting herbicide recently registered in China for controlling grass and broadleaf weeds in wheat. It is a novel herbicide, and its potential harm to soil ecosystems has not yet been reported. This study investigates the influence of QYM201 on soil enzyme activity and microorganism quantities in two different soils at concentrations of 0.1, 1, and 5 mg kg-1 soil. Results indicate that QYM201 initially inhibited soil protease, urease, and sucrase activity and this effect increased with concentration. During the later stages of incubation, inhibitory effects gradually weakened and by the end of the experiment (45 days), enzyme activity was restored to control levels. Catalase activity was stimulated by QYM201, with significant differences observed between the QYM201-treated groups and the control at the onset of exposure. This stimulation effect decreased during the later stages of the experiment. However, catalase activity was still significantly higher at the end of the experiment compared to the control. The effects of QYM201 on soil microorganisms differed. Initially, bacteria and actinomycetes quantities were decreased by QYM201 (10 days). As the incubation progressed, microorganism quantities in the lower concentration groups (0.1 and 1 mg kg-1 soil) were restored to control levels, while those of the high concentration group (5 mg kg-1 soil) did not fully recover. QYM201 did not significantly impact the quantity of fungi. The half-life and degradation rate constant (k) of QYM201 for the two studied soil types were 23.1 days and 16.1 days, and 0.030 and 0.043 day-1, respectively.

Effects of mesotrione on oxidative stress, subcellular structure, and membrane integrity in Chlorella vulgaris.

Mesotrione is a selective herbicide used to prevent weed attack of corn. It is extensively used, and hence, is being increasingly detected in aquatic ecosystems and may exert adverse effects on aquatic organisms. To evaluate the effects of mesotrione on photosynthesis-related gene expression, antioxidant enzyme activities, subcellular structure, and membrane integrity in algal cells, a comprehensive study was conducted using the green alga, Chlorella vulgaris. Exposure to 4-50 mg/L mesotrione resulted in a progressive inhibition of cell growth, with a 96-h median inhibition concentration (96 h- ErC50) value of 18.8 mg/L. Further, 18 and 37.5 mg/L mesotrione affected the algal photosynthetic capacity by decreasing the cell pigment content and reducing transcript abundance of photosynthesis-related genes. Mesotrione induced oxidative stress, as confirmed by increased cellular levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and altered antioxidant enzyme activities. It also damaged the algal cellular structure, observed as plasmolysis, blurred organelle shape, and disruption of the chloroplast structure. Flow cytometry analysis revealed that mesotrione exposure led to uneven cell growth and interior irregularities in the algal cell. The apparent propidium iodide (PI) influx also confirmed that the herbicide induced damage of the cell membrane integrity. This study will facilitate the understanding of the physiological and morphological changes induced by mesotrione in C. vulgaris cells, and provide basic information for understanding the biological mechanisms of mesotrione-induced algal toxicity.

Responses of Harmonia axyridis (Coleoptera: Coccinellidae) to sulfoxaflor exposure.

Harmonia axyridis is an important predator of several pest species and is part of many Integrated Pest Management (IPM) programs. To assess the risks of pesticide application to H. axyridis, we studied the effects of sulfoxaflor on H. axyridis larvae. At 72 h after treatment, the acute toxicity LR50 was 311.9476 g a. i. ha-1 by the residual contact method. This result indicated low-contact toxicity against second-instar H. axyridis larvae. The LR50 of the F1 generation decreased from 69.96 to 36.41 g a. i. ha-1 in a long-term toxicity test. The daily hazard quotient (HQ) for H. axyridis larvae lowered the safety threshold value in the first 5 d. However, the HQ values were greater than 2 during days 6-18 after sulfoxaflor treatments. We determined the No Observed Effect Application Rates of sulfoxaflor on the survival (<11.25 g a. i. ha-1), duration of larval and pupal stages (45 g a. i. ha-1), adult stage (90 g a. i. ha-1), total pre-oviposition period, adult pre-oviposition period (45 g a. i. ha-1), and reproduction (11.25 g a. i. ha-1). Pupation, adult emergence, and eggs counts of H. axyridis were reduced after sulfoxaflor treatments. The predation ability and population demography parameters were significantly impaired by higher application rates. At 90 g a. i. ha-1 or less, sulfoxaflor was slightly harmful to H. axyridis but a rate of 180 g a. i. ha-1 was moderately harmful. These results demonstrated that sulfoxaflor is harmful to H. axyridis when applied at high application rates.

Toxicity of thifluzamide in earthworm (Eisenia fetida).

An increase in the area treated with the fungicide thifluzamide has triggered concerns for soil ecosystem service providers such as earthworms. Here, we assessed effects of thifluzamide on earthworm (Eisenia fetida) biomarker indicators of stress responses and reproduction following exposure to 0, 0.1, 1.0, and 10.0 mg of thifluzamide kg-1 soil for 7, 14, 21, and 28 d (biomarker indicators) and 30 d (reproduction). Growth and reproduction were inhibited by exposure to thifluzamide at 10.0 mg/kg, and the activities of succinate dehydrogenase (SDH) and respiratory chain complex II were inhibited by exposure to 1.0 and 10.0 mg/kg thifluzamide for the majority of the 28-d experiment. Reactive oxygen species (ROS) increased across all thifluzamide treatments, and the activities of superoxide dismutase (SOD) and glutathione-S-transferase (GST) tended to be inhibited by thifluzamide. Upon exposure to thifluzamide, the activities of catalase (CAT) and guaiacol peroxidase (POD) initially increased and then decreased. Increased levels of malondialdehyde (MDA) were detected only at seven days after exposure, and genotoxicity increased as the thifluzamide concentration increased. The results suggest that thifluzamide presents a potential risk to earthworms at the concentration of 10.0 mg/kg, and its use should be moderated to reduce damage to soil ecosystem function.

Chlorantraniliprole against the black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae): From biochemical/physiological to demographic responses.

Agrotis ipsilon (Lepidoptera: Noctuidae) is a major underground pest that damages many agricultural crops in China and other countries. A diet-incorporation-based bioassay was conducted to evaluate the sublethal effects of the novel anthranilic diamide chlorantraniliprole on the nutritional physiology, enzymatic properties and population parameters of this cutworm. Chlorantraniliprole exhibited signs of active toxicity against third instar larvae of A. ipsilon, and the LC50 was 0.187 µg.g-1 of artificial diet after treatment for 72 h. The development time of the larval, pupal and adult stages was significantly affected after chlorantraniliprole exposure, compared to the control treatment. Relative to the control treatment, chlorantraniliprole decreased pupal and adult emergence rates, fecundity and fertility and increased the proportions of developmental deformities, the adult preoviposition period (APOP) and the total preoviposition period (TPOP). Furthermore, compared to those treated with the control, A. ipsilon larvae treated with low doses of chlorantraniliprole decreased food utilization and nutrient content (protein, lipid, carbohydrate, trehalose), showed lower pupal weights and growth rates. Compared with the control treatment, chlorantraniliprole significantly reduced digestive enzyme activities and observably increased detoxifying and protective enzyme activities and hormone titers. Importantly, these chlorantraniliprole-induced changes affected life table parameters of the cutworm. These results suggest that chlorantraniliprole at low concentrations can impair A. ipsilon development duration, normal food consumption and digestion process, enzymatic properties, hormone levels, fecundity and population levels. Chlorantraniliprole exhibit the potential to be exploited as a control strategy for this cutworm.

Growth, DNA damage and biochemical toxicity of cyantraniliprole in earthworms (Eisenia fetida).

Cyantraniliprole is a second-generation diamide insecticide that exhibited excellent biological efficacy against a variety of pests. To assess the toxic impact of cyantraniliprole on earthworms, the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), activities of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST), as well as DNA damage were measured after exposed to five cyantraniliprole concentrations ranging from 0 to 10.00 mg/kg for 7, 14, 21 and 28 days. In most treatment groups, the ROS levels increased significantly before exposure time of 14 days and then returned to normal levels. However, the SOD and CAT activities showed different response with activities were first significantly decreased and subsequently increased. The peroxidase (POD) activity showed no significant differences between treatment and control groups at first and then significantly increased. However, the opposite pattern characterized the GST activity. Also, maybe being dose-dependent before 14 days. The MDA concentration was used as a measure of lipid peroxidation (LPO). During experiment period, the MDA concentrations significantly increased when treated by this pesticide. The olive tail moment (OTM) was used as a measure of DNA damage. At higher concentrations of cyantraniliprole and longer exposure times, the OTM gradually increased, and DNA damage in the earthworms gradually increased. The weight of the high-dose (i.e., 5 mg/kg, 10 mg/kg) earthworms showed a significant trend of decrease phenomenon. Overall, the results suggest that sub-chronic exposure to cyantraniliprole causes DNA damage and LPO, weight loss and growth inhibition, leading to antioxidant defence responses in earthworms.

Compatibility of chlorantraniliprole with the generalist predator Coccinella septempunctata L. (Coleoptera: Coccinellidae) based toxicity, life-cycle development and population parameters in laboratory microcosms.

Coccinella septempunctata is a common insect predator that provides biological control of many destructive arthropod pests. An assessment of the toxicity of pesticides to predators is a necessary component of Integrated Pest Management (IPM) strategies. In order to evaluate the risks of field insecticide application, we studied the influence of chlorantraniliprole on C. septempunctata larvae using different exposure doses. Chlorantraniliprole exhibited low contact toxicity against 2nd instar larvae of C. septempunctata with the LR50 was 482.7063 g a.i. ha-1 by after a 72-h exposure. In a long-term test, the LR50 of chlorantraniliprole for C. septempunctata decreased from 88.97 to 58.22 g a.i. ha-1, while the hazard quotient (HQ) values were below the threshold value of 2 during the entire observation period. This indicated a low toxicity risk from insecticide exposure. The total effect (E) suggested that chlorantraniliprole could be classified as harmless/slightly harmful to C. septempunctata below/at 200% of the MRFR (the manufacturer maximum recommended field rate) of 120 g a.i. ha-1. We also determined no observed effect application rates (NOERs) of chlorantraniliprole on survival (7.5 g a.i. ha-1), developmental time (15 g a.i. ha-1) and fecundity (30 g a.i. ha-1). Chlorantraniliprole significantly reduced the pupation rate, adult emergence, egg hatchability, and predation success. Population parameters, including R0, r, λ, and T were significantly affected when C. septempunctata were treated with chlorantraniliprole at higher label rates. These results demonstrated that the use of chlorantraniliprole may reduce C. septempunctata population levels and the level of biological control provided by this species.

Effects of insect growth-regulator insecticides on the immature stages of Harmonia axyridis (Coleoptera: Coccinellidae).

Harmonia axyridis is an important biological control predator in greenhouses and agricultural fields, and it plays a significant role in the integrated pest management (IPM) of several arthropod pests. We studied the effects of eight insect growth-regulator insecticides (IGRs) on immature stages of H. axyridis by residual toxicity (eggs and pupae) and contact toxicity (larvae) to evaluate the risk of using these IGRs in IPM systems. Diflubenzuron, hexaflumuron and lufenuron caused more than 80% mortality to H. axyridis eggs, larvae and pupae, respectively. Pyriproxyfen was also highly harmful to larvae and pupae of H. axyridis. In contrast, methoxyfenozide and buprofezin caused little mortality and were classified as slightly harmful to immature stages based on a reduction coefficient. In addition to mortality and developmental time, the fecundity, fertility and deformed eggs of offspring were affected, when the predators were exposed to IGRs. Benzoylphenylurea insecticides significantly reduced H. axyridis female fecundity and fertility and increased the number of deformed eggs. The adverse effects are closely connected with the developmental stages of the predators and types and methods of insecticides exposed. All IGRs affected, to some extent, the life-table parameters of H. axyridis when the insecticides applied on immature stages at the highest field rates. Tebufenozide, diflubenzuron, hexaflumuron and lufenuron significantly reduced the Ro, T, r and λ of beetles exposed to the insecticides. The results indicate that IGRs could disturb the population growth and biocontrol activities of H. axyridis when applied at the highest field label rates. Additional studies should be conducted to assess the effects of IGRs on H. axyridis under field conditions before incorporating them in IPM strategies.