The relationship between insulin-like growth factor-1, growth hormone, thyroid hormones and insulin in chickens selected for growth

The concentrations of circulating insulin-like growth factor I, growth hormone, insulin and thyroid hormones were measured in broilers selected for an increase in growth, broilers in which selection pressure was relaxed and in White Leghorns. Growth hormone levels increased in all lines between 3 and 4 weeks of age followed by a decline to adult levels. The lines with the slowest rate of growth had the highest growth hormone concentrations. Insulin-like growth factor I concentrations increased significantly in all three lines of birds during the 10 weeks of study and was significantly correlated with the increase in body weight. There were no consistent differences in plasma IGF-1 levels between the lines. Thyroxine levels increased consistently throughout the study but the levels of triiodothyronine decreased between 5 and 6 weeks of age in all lines. There were no consistent changes in plasma insulin levels. The highest rate of growth in these animals is accompanied by an increase in growth hormone concentration followed by an increase in plasma IGF-1. However, despite differences in plasma growth hormone, plasma concentrations of IGF-1 are not different between lines and are not related to between line differences in growth rate.     

甘氨酰谷氨酰胺对鸡生长、内源激素及相关基因表达的影响

9日龄优质粤黄鸡360只，随机分为4组，每组90只，通过饮水添加不同剂量的甘氨酰谷氨酰胺（Glycyl—Glu—tamine，Gly—Gln，剂量分别为0％、0．01％、0．05％和0．1％），观察Gly—Gln对粤黄鸡生长性能、内源激素和肝脏GHRmRNA、肌肉IGF—IR mRNA的影响。结果显示：一定剂量的Gly—Gln显著提高了试验组鸡的平均体重、胸肌率和腿肌率，显著降低了腹脂率；添加Gly—Gln的各试验组鸡血清中IGF-1、TSH、T3、T4水平均明显升高，而血清胰岛素水平降低；添加Gly—Gln的各试验组鸡肝脏GHRmRNA表达量略高于对照组，但差异不显著，而肌肉IGF—IRmRNA表达量低于对照组，其中0．01％和0．1％Gly—Gin组差异显著。以上结果提示，Gly—Gin可通过提高鸡血液IGF一1、TSH、T3、T4水平，降低血液胰岛素浓度而发挥其促生长和改善胴体品质的作用。     

Variations in chicken breast meat quality: implications of struggle and muscle glycogen content at death

1. Pectoralis major (P. major) muscle pH and meat quality traits were studied in relation to bird response to ante-mortem stress in three chicken lines: a fast-growing standard line (FGL), a slow-growing French 'Label Rouge' line (SGL) and a heavy line (HL). Ninety-nine birds of the three genetic types were slaughtered at their usual marketing age (6, 12 and 6 weeks for FGL, SGL and HL birds, respectively) on the same day. The birds of each line were divided into three different ante-mortem treatment groups: minimum stress (shackling for 10 s) (C), shackling for 2 min (SH) and acute heat plus shackling stress (exposure to 35 degrees C for 3.5 h and shackling for 2 min before stunning) (H + SH). 2. Regardless of chicken line, wing flapping duration (WFD) between hanging and stunning was strongly negatively related to P. major muscle pH at 15 min post-mortem. It was also moderately negatively related to P. major muscle glycolytic potential (GP), which represents glycogen level at death. Increasing WFD induced an increased ultimate pH (pHu) only in HL. The consequences of increased WFD for breast meat traits were dependent on the chicken line: it induced lower L* and b* and higher a* and drip loss in SGL while it only increased breast a* in HL birds. By contrast, WFD variations did not alter breast meat quality traits of FGL birds. Regardless of the chicken line, increased GP was associated with lower pHu and higher L* and drip loss. In SGL, it also increased b* and decreased curing-cooking yield of breast meat. 3. Struggling activity on the shackle line and muscle glycogen content at death could partly explain line and pre-slaughter variations in breast meat pH and quality traits. The water holding capacity of the raw and cooked meat was impaired by long shackling in the case of SGL birds while it was barely affected by ante-mortem conditions in the two standard lines. In conditions which minimised bird struggling (C), SGL and FGL birds had meat with a better water holding ability than that of broilers from the heavy line. However, when broilers were subjected to SH or H + SH conditions, the breast meat water holding capacity of SGL birds was lowered to the same level as that of the heavy line birds.     

壳聚糖对肉仔鸡生长性能及血清生化指标的影响

试验选用1日龄AA雄性肉仔鸡270只,随机分到5个日粮处理组,进行为期42d的饲养试验。5种日粮是在基础日粮中加入0、50、100、150mg/kg的壳聚糖和50mg/kg的金霉素。结果表明:日粮中添加100mg/kg壳聚糖在提高日增重趋势的同时,提高了饲料转化效率,效果优于金霉素。在血清生化指标方面,100mg/kg壳聚糖组相比对照组降低了血清中TC、TG含量(P<0.05),提高了TPI、GF-1和GH含量(P<0.05),而对葡萄糖和尿酸含量无影响(P>0.05)。初步确定壳聚糖在肉鸡日粮中的适宜添加量为100mg/kg。壳聚糖的促生长作用可能与提高了血清中GH和IGF-1的分泌有关。     

Effects of weaning on somatotrophic gene expression and circulating levels of insulin-like growth factor-1 (IGF-1) and IGF-2 in pigs

The present study evaluated somatotrophic gene expression in liver, muscle and adipose tissue 4 d after weaning, a time point corresponding to greatly reduced serum concentrations of insulin-like growth factor (IGF)-1 and IGF-2 in pigs. Two-week-old barrows were either cross-fostered to a sow (SOW, N = 8) or weaned and fed a phase 1 diet containing either 0 or 7% spray-dried plasma (NP, N = 8 and SDP, N = 8; respectively). Piglets were allocated such that two size groups were equivalently represented in each experimental group (small, 3.5–4.3 kg and large, 4.6–5.7 kg). Animals were weighed daily and sacrificed 4 d after weaning for blood and tissue collection. Daily gains of the SOW piglets were significantly greater than those of the weaned pigs for the first 3 d of the experiment (P < 0.0001). Weight gains in the SOW and SDP pigs between d 3 and 4 were equivalently elevated relative to the NP pigs (P < 0.0001). Serum IGF-1 and IGF-2 concentrations were decreased in both NP and SDP compared to SOW (P < 0.0001). Serum IGF-2 levels were significantly lower in small piglets (P = 0.006). A Weaning Group X Size interaction was noted for liver IGF-2 mRNA (P < 0.03), reflecting a higher level of expression in large SOW piglets relative to small SOW piglets. Weaning did not affect IGF-1, IGF-2, or growth hormone (GH) receptor mRNA levels in liver, muscle, or fat (P > 0.05). Liver IGF-binding protein (IGFBP)-3 and acid-labile subunit (ALS) mRNA levels also were unaffected by weaning. Small pigs had lower levels of liver ALS (P = 0.0003), muscle IGF-2 (P = 0.02), and muscle GH receptor (P = 0.006) mRNAs. In contrast, adipose tissue IGF-1 and IGF-2 mRNA levels were greatest in the small piglets (P = 0.001 and 0.029, respectively).     

杨木低聚木糖对肉鸡生长性能、肠道消化酶活性和短链脂肪酸含量及血清激素水平的影响

本试验以肉鸡为研究对象,对以杨木屑为原料、采用醋酸催化法制取的低聚木糖进行评价,研究低聚木糖对肉鸡生长性能、肠道消化酶活性和短链脂肪酸含量及血清激素水平的影响,探讨低聚木糖的促生长机制,为醋酸催化法生产低聚木糖的应用提供理论依据.选用120只1日龄爱拔益加肉公鸡,随机分为2个组,即对照组和低聚木糖组,每组6个重复,每个...     

Ubiquitin gene expression and ubiquitin conjugation in chicken muscle do not reflect differences in growth rate between broiler and layer birds.

Previous work has shown that chicken strains selected for growth (broilers) degrade muscle proteins less rapidly than those selected for egg laying. They also have decreased calpain and increased calpastatin content in breast muscle. This study aimed to test the hypothesis that these differences correlate with changes in the ATP- and ubiquitin-dependent proteolytic system. Chickens of a broiler strain (Ross 1) and a layer strain (ISABrown) were reared to the age of 4 wk under identical conditions with ad libitum access to feed and water. Mean fractional growth rates were 10.4%/d for broilers and 7.4%/d for layers. Feed intake measured in the last week of the trial was slightly greater in layer birds (.11 and .12 g x g body weight(-1) x d(-1) for broilers and layers respectively; P < .006). Polyubiquitin (UbI) messenger RNA was abundant in the muscles of these well-fed birds, but it showed little difference between strains. Muscle did not significantly express the UbII polyubiquitin gene. The ATP-dependent system conjugating ubiquitin to endogenous proteins had greatest activity in the gastrocnemius muscle of broiler birds but was not significantly different between breeds. Proteins cross-reactive with antisera to recombinant human proteasome regulatory subunits MSS1 (multicopy suppressor of SUG 1; S7) and TBP1 (tat binding protein 1; S6') were present in muscle homogenates from both strains of bird. The chick equivalent of TBP1 was more abundant in breast muscle of broiler birds than in leg muscle, or in either muscle of layers. Antiserum to recombinant yeast subunit mts2 (mitosis temperature sensitive gene 2; S4) did not react with any protein of the expected size but detected a 30-kDa peptide that was not associated with the 26S proteasome; this was found only in muscle from the layer strain. Hence, during normal growth of chickens, rates of protein degradation are not controlled by the expression of ubiquitin mRNA or the conjugation of ubiquitin. However, the composition of the 26S proteasome may be a regulatory factor.     

5种品系肉用仔鸡血清IGF-Ⅰ和甲状腺激素与生产性能相关性研究

为了对肉鸡选种选育提供科学依据,本研究选择5个不同生长速度的肉鸡品系,相同饲养条件下饲养8周,记录饲料消耗及生长速度,于第8周末宰杀,采集血清,放免测定法测定其中的IGF-Ⅰ、T3和T4浓度。结果表明生长最慢的烟霞鸡具有显著高水平的T3和显著低水平的IGF-Ⅰ以及显著低的全净膛率。动物的生长速度与血清IGF-Ⅰ水平呈现显著正相关,与血清T3水平呈现显著负相关。血清IGF-Ⅰ与T3水平呈现显著负相关。全净膛率与血清IGF-Ⅰ及T4水平呈显著正相关。肉鸡生长速度与血清IGF-Ⅰ及T3水平有密切关系,禽类生长发育的调节机制显著不同于哺乳类。     

Effects of tryptophan supplementation on cashmere fiber characteristics, serum tryptophan, and related hormone concentrations in cashmere goats

This study was designed to investigate the effects of tryptophan (Trp) supplementation on cashmere fiber characteristics and on serum Trp, melatonin (MEL), prolactin (PRL), insulin-like growth factor 1 (IGF-1), triiodothyronine (T(3)), and thyroxine (T(4)) concentrations in cashmere goats during the cashmere fast-growth period. Thirty-six Liaoning cashmere wether goats were stratified on the basis of body weight (28 ± 0.8 kg) and assigned randomly to 1 of the following 4 rumen-protected Trp treatments: 0, 2.0, 4.0, and 6.0 g per goat per day. The experimental period lasted 137 d. Blood samples were collected monthly during the daytime (8:00 AM) and at night (8:00 PM). Tryptophan supplementation improved cashmere growth rates, cashmere weight, and body weight (P = 0.001) and increased serum Trp levels, nighttime MEL concentrations, IGF-1, and T(3) and T(4) concentrations (P < 0.05). Across the treatments and sampling months, a highly positive correlation between cashmere growth rate and nighttime serum MEL concentrations was observed (r = 0.879, P = 0.001). A moderately negative correlation between cashmere growth rates and serum PRL concentrations during the day and at night (r(day) = -0.645, P = 0.007; r(night) = -0.583, P = 0.018) was observed. A moderately positive correlation between the cashmere growth rate and the daytime serum IGF-1 concentration (r = 0.536, P = 0.032) was observed, and no correlation was found between the cashmere growth rate and the other serum hormone concentrations. These data indicate that changes in serum concentrations of MEL, IGF-1, and PRL are related to cashmere growth in Liaoning cashmere goats during the cashmere fast-growth period. Under the experimental conditions of the current trial, we suggest that Trp may promote cashmere growth by increasing daytime IGF-1 and nighttime MEL secretion.     

Muscle structure and gene expression in pectoralis major muscle in response to deep pectoral myopathy induction in fast- and slow-growing commercial broilers

1. The objective of this study was to determine muscle structure and gene expression in pectoralis major (p. major) muscle of broilers in response to deep pectoral myopathy (DPM) induction.

2. A total of 160 chickens from slow- and fast-growing broilers were raised under same conditions. Half of the broilers from each strain were encouraged to wing flap when they reached 2800 g body weight. Pectoralis minor (p. minor) muscle of the broilers was inspected for the occurrence of DPM and p. major samples were collected from broilers with or without DPM. The muscle fibre area and number, capillary number and the signalling pathways of vascular development (vascular endothelial growth factor A, VEGFA) and muscle contraction regulation (actin alpha 1, ACTA1; myosin light chain kinase 2, MYLK2 and ATPase Ca⁺² transporting gene 1, ATP2A1) were studied in p. major muscle.

3. DPM induction increased fibre area of p. major muscle with a greater rate in the slow-growing strain compared with fast-growing line. Although the capillary number was higher in slow-growing compared with fast-growing broilers, in the case of DPM induction, the number of capillaries was similar between strains.

4. Expression of VEGFA, MYLK2 and ATP2A1 was greater in slow- than in fast-growing broilers. DPM induction increased expression of ACTA1, VEGFA and ATP2A1 in p. major muscle of broilers from both strains; however, MYLK2 expression was downregulated.

5. Changes in capillary density and expression of VEGFA found in the p. major muscle of broilers with DPM suggest increased blood flow to increase oxygen availability. The upregulation of ATP2A1 by DPM induction could be attributable to alterations in calcium ion transportation from the cytoplasm into the sarcoplasmic reticulum.

6. The results are evidence of changes in muscle structure and gene expression pathways in p. major muscle of broilers with DPM.     

Let me sleep! Welfare of broilers (Gallus gallus domesticus) with disrupted resting behaviour

Perching is important for broiler welfare, however, hampered by body weight. In a mixed flock, resting behaviour and location were compared between three broiler hybrids (Rowan Ranger, Hubbard CYJA57 &; Ross 308; n?=?100/hybrid), differing in growth. Rearing was in a large littered pen (1.84 birds/m²), with perches. Behaviour and position was observed in focal birds on daytime and as group scans on daytime (days 11, 45, 61 and 80) and night-time (days 63, 70 and 77). Birds were slaughtered at 84 days and accumulated mortality in fast-growing birds was 20% and 2% in slow-growing. Resting frequency did not differ though fast-growing broilers perched less and lower, at night (P?P?P?相似文献   

不同品种白羽肉鸡肌肉品质及营养成分的比较研究

为研究小型白羽肉鸡与快大型白羽肉鸡肌肉品质及营养成分差异,试验选取WOD168配套系为小型白羽肉鸡代表,选取科尼什与白洛克杂交后代为快大型肉鸡代表,于6周龄屠宰后进行肉品质及肌肉营养成分测定.结果显示:小型白羽肉鸡比快大型肉鸡有更高的剪切力,更小的肌纤维直径和更高的肌纤维密度;小型白羽肉鸡胸肌粗蛋白含量较快大型肉鸡高,...     

性别对3～6周龄AA肉鸡生产性能、血液指标的影响

为研究公母雏生产性能差异的原因,选择2周龄AA＋公母各75羽AA肉鸡进行饲养试验,观测生产性能指标,用酶联免疫法测定4周龄和6周龄肉鸡血液中生长激素等17项指标。试验结果表明,3～6周龄AA肉鸡公雏的平均日采食量、平均日增重和料重比均极显著高于母雏（P＜0.01）。4周龄肉鸡公雏血液EPI、NE、TSH、GH、IGF-Ⅰ、T4高于母雏,而LP、T3、INS低于母雏,T3、INS达到极显著水平（P＜0.01）。6周龄肉鸡公雏ACTH和NE高于母雏, NE达到极显著水平（P＜0.01）,其他指标无明显趋势和差异。     

Insulin-like growth factor type-1 receptor down-regulation associated with dwarfism in Holstein calves

Perturbations in endocrine functions can impact normal growth. Endocrine traits were studied in three dwarf calves exhibiting retarded but proportionate growth and four phenotypically normal half-siblings, sired by the same bull, and four unrelated control calves. Plasma 3,5,3'-triiodothyronine and thyroxine concentrations in dwarfs and half-siblings were in the physiological range and responded normally to injected thyroid-releasing hormone. Plasma glucagon concentrations were different (dwarfs, controls>half-siblings; P<0.05). Plasma growth hormone (GH), insulin-like growth factor-1 (IGF-1) and insulin concentrations in the three groups during an 8-h period were similar, but integrated GH concentrations (areas under concentration curves) were different (dwarfs>controls, P<0.02; half-siblings>controls, P=0.08). Responses of GH to xylazine and to a GH-releasing-factor analogue were similar in dwarfs and half-siblings. Relative gene expression of IGF-1, IGF-2, GH receptor (GHR), insulin receptor, IGF-1 type-1 and -2 receptors (IGF-1R, IGF-2R), and IGF binding proteins were measured in liver and anconeus muscle. GHR mRNA levels were different in liver (dwarfs相似文献   

Immune responses to an Eimeria acervulina infection in different broilers lines

The (T-cell) immune responses of two different broiler lines to a primary Eimeria acervulina infection were investigated. The lines used were a commercial fast-growing broiler line and a slow-growing type of broiler as used in organic farming. Seven-day-old broilers of both lines were infected with 5 x 10(4) oocysts of E. acervulina. The animals were weighed and a species-specific real-time PCR was used to quantify the total amount of parasites in the duodenum. In the fast-growing line, a lower parasite load was seen from day 4 onwards compared to the slow-growing line. In both lines the intestinal peak of Eimeria DNA was observed at day 5 post infection (p.i.). In the duodenum no increase in CD4(+) T-cells was found in both infected lines, but a fast increase in CD8(+) T-cells was observed in the fast-growing line. At day 3 p.i. in the slow-growing broilers an IL-18 mRNA response was observed. At day 4 p.i. strong IFN-gamma and IL-8 mRNA responses were found in both lines. No IL-4 mRNA responses were found in the duodenum. In conclusion, both lines have different growth rates and control and infected conditions. Based on the kinetics of observed phenomena a primary infection with E. acervulina in 7-day-old broilers seems to generate an early CD8alpha(+) response in fast-growing broilers compared to the slow-growing broilers. This difference in immune reaction after an E. acervulina infection could result in a different Eimeria load in the duodenum.     

红三叶异黄酮对肉鸡血液几种内源性激素水平的影响

本试验旨在研究饲粮中添加红三叶异黄酮对肉鸡血液几种内源性激素水平的影响。选取1日龄雄性爱拔益加肉仔鸡240羽,随机分为4组(每组4个重复,每个重复15只),分别饲喂在基础饲粮中添加0(对照组)、10(试验Ⅰ组)、20(试验Ⅱ组)、30 mg/kg(试验Ⅲ组)红三叶异黄酮的试验饲粮。试验持续7周。结果表明:试验Ⅰ组和试验Ⅱ组的平均日增重显著或极显著高于对照组和试验Ⅲ组(P<0.05或P<0.01)。各试验组料重比均低于对照组,但差异不显著(P>0.05)。血清生长激素(GH)水平,试验Ⅱ组在21、35和49日龄均显著或极显著高于对照组(P<0.05或P<0.01),试验Ⅰ组在49日龄、试验Ⅲ组在21日龄显著或极显著高于对照组(P<0.05或P<0.01);血清类胰岛素生长因子Ⅰ(IGF-Ⅰ)水平,各试验组在21日龄均显著高于对照组(P<0.05),试验Ⅱ组在49日龄显著高于对照组和其他试验组(P<0.05);血清三碘甲腺原氨酸(T3)水平,试验Ⅰ组在35和49日龄、试验Ⅱ组在49日龄均显著或极显著高于对照组(P<0.05或P<0.01);血清四碘甲腺原氨酸(T4)水平,试验Ⅰ组和试验Ⅲ组在35日龄显著低于对照组(P<0.05);血清T3/T4,各试验组在21、35和49日龄均高于对照组,并且在35和49日龄试验Ⅰ组与对照组达到显著水平(P<0.05);血清睾酮(TESTO)水平,各组在21、35和49日龄均无显著差异(P>0.05)。由此得出,红三叶异黄酮可通过调节体内GH、IGF-Ⅰ、T3和T4水平来影响肉鸡的生长性能,饲粮中添加20 mg/kg时促生长效果较好。     

鸡肌内脂肪沉积相关候选基因筛选

本研究对课题组前期在京星黄鸡转录组研究中筛选到的与肌内脂肪（IMF）差异沉积相关的14个候选基因进行验证，检测其在中外两个鸡种群体中与胸肌IMF沉积的关联性。以98日龄慢速型地方鸡京星黄鸡和42日龄快速型白羽科宝肉鸡胸肌组织为素材，通过胸肌甘油三酯（TG）含量区分高低表型组，并检测候选基因在组间的基因表达差异。结果表明，在京星黄鸡胸肌TG高、低组间ATP结合盒亚家族B成员8（ABCB8）、脂联素（ADIPOQ）、第6号染色体开放阅读框65（BEND6）、CD74分子（CD74）、核糖基5-磷酸转移酶（FKTN）、组蛋白乙酰转移酶1（HAT1）、硫酸乙酰肝素-氨基葡萄糖3-磺基转移酶5（HS3ST5）、介体复合物亚基4（MED4）、肿瘤坏死因子超家族成员8（TNFSF8）和TNFAIP3相互作用蛋白1（TNIP1）共10个基因表达差异显著（P<0.05）；在科宝肉鸡TG高、低组间ADIPOQ、BEND6、FKTN、HAT1、HS3ST5、MED4和TNIP1共7个基因表达差异显著（P<0.05）；ADIPOQ、FKTN、HAT1、HS3ST5、MED4和TNIP1共6个基因在两个品种中差异表达趋势一致（P<0.05）。本研究提供了鸡IMF沉积相关新候选基因，为IMF分子调控机理研究和相关分子标记筛选研究奠定了良好的基础。     

Organic poultry production in the United States: Broilers

Since the USDA implemented the National Organic Program, the growth of the organic food market has continued to increase, with organic poultry as leading products. Organic livestock husbandry practices focus on living conditions that permit natural behaviors and provide outdoor access, preventive health management with a prohibition of antibiotics or other drugs (although vaccines can be used), and organic feed. Organic feed is raised without synthetic fertilizers and pesticides; pastures to which birds have access must also be organic. Hatcheries are currently not required to be organic, and conventional chicks may be used if they are under organic management by the second day after hatching. Although alternative, slow-growing genotypes are used in organic production in the European Union, conventional genetics are used in the United States. Poultry products, including meat and eggs, must be handled organically. Most synthetic materials are not permitted in organic food production, whereas most natural materials are; however, the National Organic Program National List specifies which materials are allowed. Of particular interest is an impending ban on the use of synthetic methionine in organic poultry diets. Research in the United States has examined alternative strategies, including the use of slow-growing broilers that are less heavily muscled than conventional fast-growing meat birds, but has not shown these birds to have lower methionine requirements. Research has also examined sensory differences between specialty and conventional meat chickens in the United States. Consumer panelists indicated no preference between these products, although trained panelists found some differences in the flavor of thigh meat. More meat quality differences were due to genotype than to outdoor access. Breast meat from slow-growing birds was more tender than that from fast-growing birds. Outdoor access resulted in leaner meat, but only in the case of slow-growing birds. As interest grows in specialty and organic poultry meat products, additional research is needed.     

1～21日龄黄羽肉鸡钠、氯的需要量

本试验旨在通过研究饲粮不同钠、氯水平对黄羽肉鸡生长性能、排泄物含水率、血清指标、肠道钠-葡萄糖共转运载体1(SGLT1)和钠/氢交换载体2(NHE2)mRNA表达量等的影响,探讨1~21日龄阶段黄羽肉鸡钠和氯的需要量及其作用机理。试验选用1日龄健康、发育良好的快大型岭南黄羽肉公鸡共1 200只,根据体重随机分成5个组,每组6个重复,每个重复40只鸡。对照组采用玉米-豆粕型基础饲粮(无额外钠、氯添加),其余各组都以钠、氯含量比1∶1设梯度,通过食盐与碳酸氢钠等量取代部分沸石粉使饲粮钠与氯含量均分别为0.1%、0.2%、0.3%和0.4%,试验期间试鸡自由采食和饮水。试验结果显示,饲粮补充钠、氯显著提高了平均日增重、平均日采食量、平均日饮水量和排泄物含水率(P0.05),显著降低了料重比和死亡率(P0.05),其中平均日增重随饲粮钠、氯水平的提高呈二次折线升高(R2=0.966,P=0.009),排泄物含水率随饲粮钠、氯水平的提高呈先升高后降低的二次曲线变化(R2=0.954,P=0.046);饲粮补充钠、氯显著提高了血清渗透压(P0.05),显著降低了血清尿酸、葡萄糖、总胆固醇和甘油三酯含量(P0.05),对血清胆囊收缩素、胃饥饿素和生长激素含量无显著影响(P0.05);饲粮钠、氯水平均为0.2%、0.4%组十二指肠NHE2 mRNA表达量和钠-钾ATP(Na+-K+-ATP)酶活性显著低于对照组(P0.05);饲粮钠、氯水平为0.2%组回肠SGLT1 mRNA表达量显著高于对照组和0.4%组(P0.05)。结果提示,本试验条件下,以生长性能为评定指标,根据方差分析和多重比较得到,1~21日龄阶段快大型黄羽肉鸡饲粮适宜钠、氯水平均为0.2%;通过非线性回归模型估测得到,饲粮适宜钠、氯水平均为0.14%。