This study was conducted to investigate the effects of ambient temperature on the growth performance, fat deposition, and intestinal morphology of geese from 28 to 49 d of age. A total of 120 twenty-eight-day-old geese were randomly allotted to 5 environmentally controlled chambers with ambient temperatures set at 18, 21, 24, 27, and 30°C from 28 to 49 d of age, respectively. The feed intake, 49 d body weight, and weight gain decreased linearly or quadratically (P < 0.05) as ambient temperature increased and declined to a minimum when the temperature increased to 30°C. The feed/gain showed a linear or quadratic (P < 0.05) increasing response to increasing temperature. According to broken-line regression, the upper critical levels of ambient temperature from 28 to 49 d of age for weight gain and feed intake were 25.19 and 23.97°C, respectively. As ambient temperature increased from 18 to 30°C, the abdominal fat weight, abdominal fat rate, and subcutaneous fat thickness decreased linearly (P < 0.05) and were accompanied by linearly increasing liver fat content (P < 0.05), but the ambient temperature had no effect on intermuscular fat width or breast muscle fat content (P > 0.05). There were no differences in jejunal, ileal, or cecal morphology for geese raised at 18, 21, 24, 27, and 30°C (P > 0.05). The duodenal villus height showed a linear decreasing response to increasing ambient temperature, but the ambient temperature had no effect on crypt depth, villus width, muscularis thickness, or villus height/crypt depth of the duodenum (P > 0.05). These results indicate that high ambient temperature decreased growth performance and fat deposition and impaired duodenal morphology of geese. Under our experimental conditions, we recommend that the upper critical ambient temperature for geese from 28 to 49 d of age be 25.19°C.

This study was conducted to investigate the effects of citric acid (CA) supplementation on growth performance, intestinal morphology, intestinal microbiota, and blood parameters of geese from 1 to 28 d of age and evaluate the optimum additional level of citric acid. A total of 180 one-day-old male goslings were randomly allotted to 5 treatment groups of 36 birds with 6 replications. The control group was fed a basal diet, and the other groups were fed the basal diet supplemented with 0.25, 0.50, 1.00, and 2.00% of citric acid, respectively. The results showed that goslings fed the diet supplemented with 1.00% CA had higher final body weight (FBW) and average daily gain (ADG) than other groups (P < 0.05). The CA supplementation at 0.25 to 1.00% improved the morphology of duodenum or jejunum (P < 0.05). The jejunal content pH value was significantly reduced with the addition of CA compared with the control group (P < 0.05). As citric acid levels increased, the IgA concentrations in plasma increased and then decreased, and the goslings fed 1.00% CA supplementation had the highest IgA concentrations (P < 0.05). The supplementation of 1.00% and 2.00% CA in diet significantly reduced the malondialdehyde (MDA) concentration in plasma (P < 0.05). No significant difference was found on some indices related to liver function in plasma (P > 0.05), while creatinine significantly increased by the 2.00% CA supplementation (P < 0.05). Besides, the higher Coliform level in cecal content and worse intestinal morphology were observed when CA supplementation was up to 2.00%. Hence, the dietary CA supplementation (especially 1.00%) in goslings improves the growth performance, intestinal morphology, immunity and antioxidant, while excessive CA addition may cause negative effects. According to the quadratic polynomial model, the addition of CA in diet for obtaining maximum average daily feed intake (ADFI) should be 1.09% (10.9 g/kg diet) for goslings from 1 to 28 d of age.

Antibiotic and antibiotic resistance genes (ARGs) have been considered as emerging environmental contaminants and possess potential crisis to global public health. However, little is known about the differences between various configurations of two-stage combinations of constructed wetlands (CWs) on antibiotics and ARG removal from wastewater. In the study, three configurations of two-stage hybrid CWs (horizontal subsurface flow-down-flow vertical subsurface flow CWs, HF-DVF; horizontal subsurface flow-up-flow vertical subsurface flow CWs, HF-UVF; down-flow vertical subsurface flow-up-flow vertical subsurface flow CWs, DVF-UVF) were operated to evaluate their ability to remove high-concentration antibiotics (tilmicosin—TMS and doxycycline—DOC), ARGs (seven tet genes and three erm genes), intI1, 16S rRNA, and nutrients from goose wastewater. The results showed that all three hybrid CWs could remove more than 98% of TMS and DOC from wastewater, without significant difference among treatments (p > 0.05). For ARGs, DVF-UVF showed significantly higher removal efficiencies of intI1, ermB, ermC, ermF, tetW, and tetG compared to HF-UVF (p < 0.05), mainly because they might remove and arrest growth of bacteria. The relatively high removal efficiencies of NH₄⁺-N, NO₃^—N, and NO₂^--N were also observed from DVF-UVF, ranging from 87% to 95% (p > 0.05), indicating that anaerobic ammonium oxidation (anammox) might be established in the CWs. Our results demonstrate that the removal performances of antibiotics using two-stage hybrid CWs are not affected by the combined configuration, whereas the combination of DVF and UVF CWs perform better on the removal of ARGs and nutrients compared with HF-DVF and HF-UVF CWs.

This study was conducted to investigate the effect of stocking density on growth performance, feather quality, serum hormone, and intestinal development of geese from 1 to 14 d of age. A total of 450 one-day-old geese were randomly allotted to 45 battery cage (0.65 m × 0.62 m) pens according to 5 stocking densities (15, 20, 25, 30, and 35 birds/m²). The results showed that ADG and ADFI were reduced (P < 0.05) as stocking density increased from 15 to 35 birds/m², but increasing stocking density did not influence (P > 0.05) feed conversion ratio (FCR) and body measurement traits. High stocking density significantly decreased (P < 0.05) the feather quality of back, thoracoabdominal, wing, and tail. No significant difference (P > 0.05) was found in serum concentration of adrenocorticotrophic hormone, cortisol, corticosterone, triiodothyronine, and thyroxine. The weight of cecum and intestine decreased (P < 0.05) as the stocking density increased. Increasing stocking density decreased (P < 0.05) jejunal villus height and villus height-to-crypt depth ratio, and increased (P < 0.05) jejunal crypt depth and ileal crypt depth in geese. Consequently, the high stocking density could depress the growth and impaired feather quality and intestinal development of geese. Under our experimental conditions, we recommend that the stocking density of geese from 1 to 14 d of age should not more than 20 birds/m².

This study was conducted to determine the effect of feeding frequency on growth performance, carcass traits, and apparent nutrient digestibility in geese from 28 to 70 D of age. In experiment 1, a total of 240 geese were distributed in a completely randomized design into 4 treatments and 6 replicates of 10 birds each. The treatments were free access to the feeder (ad libitum) and access to the feeder 3, 4, and 5 times daily. Geese fed 3 times daily had a lower (P < 0.05) BW, ADG, and ADFI and a higher (P = 0.064) feed conversion ratio (FCR) from 28 to 41 D of age compared with the other groups. Geese fed 4 times daily had a higher (P < 0.05) ADG and ADFI and a lower (P < 0.05) FCR from 42 to 55 D of age compared with ad libitum fed geese. Geese fed 3 times daily had a higher (P < 0.05) ADG from 56 to 69 D of age than geese fed ad libitum and 4 times daily. No differences (P > 0.05) in BW, ADFI, ADG, and FCR were observed between ad libitum and feeding frequency groups from 28 to 69 D of age. Carcass traits and gastrointestinal development were not affected (P > 0.05) by feeding frequency. In experiment 2, the apparent nutrient digestibility in geese from 71 to 77 D of age fed using different feeding frequencies was determined using the total fecal collection method. Feeding frequency did not affect (P > 0.05) the apparent digestibility of DM, CP, crude ash, calcium, phosphorous, or ether extract in geese. Our study demonstrates for the first time that compensatory growth can be gained by enhancing feed intake when a lower feeding frequency is imposed on geese. Both ad libitum feeding and fixed feeding frequency for 3 to 5 times daily are suitable for geese from 28 to 70 D of age to achieve optimum production.

An experiment was conducted to investigate the effects of ambient temperature on the growth performance, blood parameter and fat deposition in geese from 14 to 28 d of age in order to establish their optimal temperature requirements. A total of 150 14-d-old geese were allocated randomly to 5 environmentally controlled chambers with ambient temperature set at 18, 21, 24, 27, and 30°C from 14 to 28 d of age, respectively. As ambient temperature increased from 18 to 30°C, the feed intake decreased linearly (P < 0.05) and was accompanied by linearly or quadratically (P < 0.05) decreasing 28-d-old body weight, weight gain, and feed/gain. The upper critical level of ambient temperature from 14 to 28 d of age for 28-d-old body weight and weight gain were 25.83 and 26.17°C, respectively. There were no differences in plasma biochemical parameters and plasma hormones between geese fed at ambient temperature regimen at 18, 21, 24, 27, and 30°C. The abdominal fat weight and abdominal fat rate decreased linearly (P ≤ 0.05) with higher ambient temperature, but the ambient temperature had no effect on subcutaneous fat thickness and intermuscular fat width. It was concluded that the upper critical temperature of the ambient temperature for geese from 14 to 28 d of age was 26.17°C and high ambient temperature could lead to growth depression.