Acid-base properties of non-protein nitrogen affect nutrients intake, rumen fermentation and antioxidant capacity of fattening Hu sheep.

This study conducted a comparison of the effects of non-protein nitrogen with different acid-base properties on feed intake, rumen fermentation, nutrient digestion and antioxidant capacity in fattening Hu sheep. Sixteen fattening male sheep (31.43 ± 2.41 kg) with permanent rumen cannulas were randomly assigned to two dietary treatments: 1% urea and 1.78% ammonium chloride (NH4Cl, AC). A 42 days experimental period was conducted, with 14 days for adaptation and 28 days for treatment. Daily feed intake was recorded and various samples including feed, feces, rumen fluid, and blood were collected at different time points during the final week. The results indicated that the urea group had significantly higher dry matter intake, average daily gain, and gain efficiency in comparison to the AC group (p < 0.01). There was no difference in rumen pH and concentration of ammonia nitrogen between different groups (p > 0.05), but the rumen pH of urea group was higher than that of the AC group at 1 and 3 h after feeding (p < 0.05). The urea group exhibited higher concentrations of total volatile fatty acids (VFA) and individual VFAs compared to the AC group at all-time points (p < 0.01). Compared to the urea group, the intake of all nutrients decreased in the AC group (p < 0.01), but the digestibility of dry matter and organic matter increased significantly (p < 0.01), and the digestibility of CP had an increasing trend (p = 0.06) in the AC group. Additionally, the urea group had lower levels of serum glucagon-like peptide-1, peptide YY, Cl, total protein and globulin than the AC group (p < 0.05). The overall levels of HCO3-, superoxide dismutase, glutathione peroxidase, catalase, albumin/globulin, blood urea nitrogen and total cholesterol in the urea group increased significantly compared to the AC group (p < 0.05). It was concluded that adding urea to the high-concentrate diet resulted in increased rumen pH and improved rumen fermentation and growth performance in fattening sheep compared to NH4Cl addition. Furthermore, urea addition improved sheep's antioxidant capacity and maintained their acid-base balance more effectively as compared to NH4Cl.

The inhibition of high ammonia to in vitro rumen fermentation is pH dependent.

Ammonia is an important rumen internal environment indicator. In livestock production, feeding a large amount of non-protein nitrogen to ruminants will create high ammonia stress to the animals, which increases the risk of ammonia toxicity. However, the effects of ammonia toxicity on rumen microbiota and fermentation are still unknown. In this study, an in vitro rumen fermentation technique was used to investigate the effects of different concentrations of ammonia on rumen microbiota and fermentation. To achieve the four final total ammonia nitrogen (TAN) concentrations of 0, 8, 32, and 128 mmol/L, ammonium chloride (NH4Cl) was added at 0, 42.8, 171.2, and 686.8 mg/100 mL, and urea was added at 0, 24, 96, and 384 mg/100 mL. Urea hydrolysis increased, while NH4Cl dissociation slightly reduced the pH. At similar concentrations of TAN, the increased pH of the rumen culture by urea addition resulted in a much higher free ammonia nitrogen (FAN) concentration compared to NH4Cl addition. Pearson correlation analysis revealed a strong negative correlation between FAN and microbial populations (total bacteria, protozoa, fungi, and methanogens) and in vitro rumen fermentation profiles (gas production, dry matter digestibility, total volatile fatty acid, acetate, propionate, etc.), and a much weaker correlation between TAN and the above indicators. Additionally, bacterial community structure changed differently in response to TAN concentrations. High TAN increased Gram-positive Firmicutes and Actinobacteria but reduced Gram-negative Fibrobacteres and Spirochaetes. The current study demonstrated that the inhibition of in vitro rumen fermentation by high ammonia was pH-dependent and was associated with variations of rumen microbial populations and communities.

Enhanced Toughness and Sound Absorption Performance of Bio-Aerogel via Incorporation of Elastomer.

In this study, Arabic gum/ carboxylic butadiene-acrylonitrite latex aerogels (AG/XNBRL) hybrid aerogel was successfully prepared by a green method, i.e., the combination of latex compounding and vacuum freeze-drying process. After that, the obtained composites were subjected to a high temperature treatment to crosslink the rubber phase. It was found that the AG in the AG/XNBRL hybrid aerogel could act as a framework to improve the dimensional stability of the aerogel, while the XNBRL phase could significantly improve the mechanical flexibility of the ensuing composite. Compared to the AG aerogel which is highly brittle in nature, the AG/XNBRL hybrid aerogel not only exhibits significantly enhanced toughness, but also shows improved thermal stability and sound absorption performances; for instance, the half weight loss (50%) temperature and average sound adsorption coefficient for aerogel containing 30 wt% XNBRL is 344 °C and 0.585, respectively, which are superior to those of neat AG aerogel. Overall, this work provides novel inspiration to prepare the mechanical robust bio-based aerogel for the sound absorption application.

Modulating social feedback processing by deep TMS targeting the medial prefrontal cortex: Behavioral and electrophysiological manifestations.

Neuroimaging studies have suggested that the medial prefrontal cortex (mPFC) is a key brain region for social feedback processing, but previous findings are largely based on correlational approaches. In this study, we use the deep transcranial magnetic stimulation (dTMS) to manipulate mPFC activity, then investigate participants' behavioral performance and event-related potentials (ERPs) during the Social Judgment Paradigm. A between-subject design was applied, such that both the active dTMS group and the sham group consisted of 30 participants. We found that the sham group was more likely to predict that they would be socially accepted (rather than rejected) by peers, but the same was not true in the active group. Additionally, this study is the first one to observe ERP signal changes in response to dTMS manipulation. ERP results show that both the expectation stage and the experience stage of social feedback processing were modulated by dTMS: (1) at the expectation stage, the P1 component was smaller in the active group than the sham group, while the stimulus-preceding negativity showed a stronger differentiating effect between positive and negative prediction in the sham group than the active group; (2) at the experience stage, the sensitivity of the late positive potential to the valence and predictability of social feedback was stronger in the sham group than the active group. These results improve our understanding about the relationship between the mPFC and social feedback processing.

Differentiating the abnormalities of social and monetary reward processing associated with depressive symptoms.

BACKGROUND: Reward dysfunction is a major dimension of depressive symptomatology, but it remains obscure if that dysfunction varies across different reward types. In this study, we focus on the abnormalities in anticipatory/consummatory processing of monetary and social reward associated with depressive symptoms. METHODS: Forty participants with depressive symptoms and forty normal controls completed the monetary incentive delay (MID) and social incentive delay (SID) tasks with event-related potential (ERP) recording. RESULTS: In the SID but not the MID task, both the behavioral hit rate and the ERP component contingent negative variation (CNV; indicating reward anticipation) were sensitive to the interaction between the grouping factor and reward magnitude; that is, the depressive group showed a lower hit rate and a smaller CNV to large-magnitude (but not small-magnitude) social reward cues compared to the control group. Further, these two indexes were correlated with each other. Meanwhile, the ERP components feedback-related negativity and P3 (indicating reward consumption) were sensitive to the main effect of depression across the MID and SID tasks, though this effect was more prominent in the SID task. CONCLUSIONS: Overall, we suggest that depressive symptoms are associated with deficits in both the reward anticipation and reward consumption stages, particularly for social rewards. These findings have a potential to characterize the profile of functional impairment that comprises and maintains depression.

I, robot: depression plays different roles in human-human and human-robot interactions.

Socially engaging robots have been increasingly applied to alleviate depressive symptoms and to improve the quality of social life among different populations. Seeing that depression negatively influences social reward processing in everyday interaction, we investigate this influence during simulated interactions with humans or robots. In this study, 35 participants with mild depression and 35 controls (all from nonclinical populations) finished the social incentive delay task with event-related potential recording, in which they received performance feedback from other persons or from a robot. Compared to the controls, the mild depressive symptom (MDS) group represented abnormalities of social reward processing in the human feedback condition: first, the MDS group showed a lower hit rate and a smaller contingent-negative variation (correlated with each other) during reward anticipation; second, depression level modulated both the early phase (indexed by the feedback-related negativity (FRN)) and the late phase (indexed by the P3) of reward consumption. In contrast, the effect of depression was evident only on FRN amplitude in the robot feedback condition. We suggest that compared to human-human interaction, the rewarding properties of human-robot interaction are less likely to be affected by depression. These findings have implications for the utilization of robot-assisted intervention in clinical practice.

Effects of dietary replacement of soybean meal with dried distillers grains with solubles on the microbiota occupying different ecological niches in the rumen of growing Hu lambs.

BACKGROUND: Diet has a profound impact on the rumen microbiota, and the impact can vary among the different rumen ecological niches (REN). This study investigated the effects of dietary replacement of soybean meal (SBM) with dried distillers grains with solubles (DDGS) on the rumen microbiota occupying different REN of growing Hu lambs. After a 9-week feeding trial, 6 lambs from each dietary treatment (SBM vs. DDGS-based diets) were slaughtered for sample collection. The microbiota of the rumen solid, liquid, and epithelium fractions was examined using amplicon sequencing analysis of bacterial 16S rRNA gene, functional prediction, and qPCR. RESULTS: No interaction of dietary protein source (PS) and REN were detected for virtually all the measurements made in this study. The DDGS substitution resulted in very limited influence on bacterial community structure. However, the metabolic pathways predicted from 16S rRNA gene sequences varied greatly between SBM- and DDGS-based diets. The populations of rumen total bacteria, fungi, sulfate-reducing bacteria (SRB), and methanogens were not influenced by DDGS substitution, but the population of protozoa was reduced. The bacterial communities in rumen solid (RS) and liquid (RL) were similar in taxonomic composition but were different in relative abundance of some taxa. In contrast, the bacterial composition and relative abundance of rumen epithelium (RE) were greatly distinct from those of the RS and the RL. In alignment with the bacterial relative abundance, the metabolic pathways predicted from 16S rRNA genes also varied greatly among the different REN. The populations of total bacteria, protozoa, and methanogens attached to the RE were smaller than those in the RS and RL, and the fungal population on the rumen epithelium was smaller than that in the RS but similar to that in the RL. On the contrary, the SRB population on the RE was greater than that in the RS and RL. CONCLUSIONS: Substitution of SBM with DDGS had greater impact to the protozoa than to the other microbes, and the microbial community structure and functions at different REN are distinct and niche-adapted.

Metagenomic analysis reveals significant differences in microbiome and metabolic profiles in the rumen of sheep fed low N diet with increased urea supplementation.

Urea is a cost-effective replacement for feed proteins in ruminant diets. However, its metabolism by the rumen microbiome is not fully understood. Here, rumen contents were collected from 18 male sheep fed one of the following three treatments: a low N basal diet with no urea (UC, 0 g/kg dry matter (DM)), low urea (LU, 10 g/kg DM) and high urea (HU, 30 g/kg DM). Principal coordinate analysis showed that the microbial composition and functional profiles of the LU treatment significantly differed from the UC and HU treatments. The genera Prevotella, Succinivibrio, Succinatimonas and Megasphaera were higher in the LU rumen, while the genera Clostridium, Ruminococcus and Butyrivibrio were enriched in the UC and HU rumen. The aspartate-glutamate and arginine-proline metabolic pathways and valine, leucine and isoleucine biosynthesis were higher in the LU rumen. The cysteine and methionine metabolism, lysine degradation and fructose and pentose phosphate metabolism pathways were higher in the UC and HU rumen. The protozoa population in the HU treatment was higher than in the UC and LU treatments. These findings suggest that the rumen microbiome of sheep fed low N diet with different urea supplementation are significantly different.

Changes in the Solid-, Liquid-, and Epithelium-Associated Bacterial Communities in the Rumen of Hu Lambs in Response to Dietary Urea Supplementation.

The rumen bacteria in the solid, liquid, and epithelial fractions are distinct and play important roles in the degradation of urea nitrogen. However, the effects of urea on rumen bacteria from the three fractions remain unclear. In this study, 42 Hu lambs were fed a total mixed ration based on concentrate and roughage (55:45, dry matter basis) and randomly assigned to one of three experimental diets: a basal diet with no urea (UC, 0 g/kg), a basal diet supplemented with low urea levels (LU, 10 g/kg DM), and a basal diet supplemented with high urea levels (HU, 30 g/kg DM). After an 11-week feeding trial, six animals from each treatment were harvested. Rumen metabolites levels were measured, and bacteria of the rumen solid, liquid, and epithelial fractions were examined based on 16S rRNA gene sequencing. Under urea supplementation, the concentrations of ammonia and butyrate in the rumen increased, whereas the concentration of propionate decreased. The population of total protozoa was the highest in the LU treatment. Prevotella 1 was the most abundant genus in all samples. The unclassified Muribaculaceae, bacteria within the families Lachnospiraceae and Ruminococcaceae, and Christensenellaceae R7 were abundant in the solid and liquid fractions. Butyrivibrio 2 and Treponema 2 were the abundant bacteria in the epithelial fraction. Principal coordinate analysis showed separation of the solid, liquid and epithelial bacteria regardless of diet, suggesting that rumen fraction had stronger influences on the bacterial community than did urea supplementation. However, the influences on the bacterial community differed among the three fractions. In the solid and liquid fractions, Succinivibrionaceae UCG 001 and Prevotella 1 showed decreased abundance with dietary urea supplementation, whereas the abundance of Oscillospira spp. was increased. Howardella spp. and Desulfobulbus spp. were higher in the epithelial fraction of the UC and LU treatments relative to HU treatment. Comparisons of predictive function in the rumen solid, liquid, and epithelial fractions among the three treatments also revealed differences. Collectively, these results reveal the change of the rumen bacterial community to dietary urea supplementation.

The right VLPFC and downregulation of social pain: A TMS study.

Previous studies have demonstrated that the right ventrolateral prefrontal cortex (RVLPFC) is crucially involved in downregulating physical and social pain. However, it remains unclear whether the RVLPFC is more specific to either physical or social pain. The present study compares the role of RVLPFC in emotion regulation in physical- and social-pain conditions using repetitive transcranial magnetic stimulation (rTMS). A total of 60 healthy participants underwent active (n = 30) or sham (n = 30) rTMS over the RVLPFC. Following each TMS session, participants performed a non-reappraisal and then a reappraisal task to downregulate imagined physical or social pain evoked by pictures. Self-reported negative emotional ratings and electroencephalogram data were recorded during the emotion regulation task. Participants were then required to rate the valence and arousal of those pictures 30 min after the task. It is found that rTMS-activated RVLPFC led to reductions in subjective negative feelings and amplitudes of the late positive potential during reappraisal; however, these effects were found exclusively in the social-pain condition. Participants also reported higher positive valence for socially, compared to physically, painful pictures after 30 min of the task. Behavioral and electrophysiological evidence both supported the functional specificity of RVLPFC in regulation of social pain. The prominent delayed effect of rTMS makes it possible to consider the potential application of rTMS-VLPFC in clinical practice for social pain relief.

Effects of Incremental Urea Supplementation on Rumen Fermentation, Nutrient Digestion, Plasma Metabolites, and Growth Performance in Fattening Lambs.

This study investigated the effects of partially substituting soybean meal (SBM) with incremental amount of urea on rumen fermentation, nutrient digestion, plasma metabolites, and growth performance in fattening lambs. Seventy fattening male lambs were sorted into two blocks according to body weight (BW) and assigned to one of five dietary treatments in a randomized block design: SBM at 170 g/kg dry matter (DM) or reduced SBM (40 g/kg DM) plus 0, 10, 20, or 30 g urea/kg DM. Compared with the lambs receiving the SBM diet, the lambs fed the reduced SBM diet plus urea had higher (p < 0.01) concentrations of ruminal ammonia, and the ruminal concentration of ammonia also increased linearly (p < 0.01) with the increasing urea supplementation. Linear and quadratic effects (p < 0.01) on the crude protein (CP) intake and digestibility were observed with the increasing urea addition to the diet. The concentrations of plasma ammonia and blood urea nitrogen (BUN) increased (linear, p < 0.01; quadratic, p < 0.01) with the increasing urea supplementation. The final BW, DM intake (DMI), average daily gain (ADG), and gain efficiency were similar (p ≥ 0.42) between the SBM group and the urea-supplemented groups. However, the DMI and ADG increased quadratically (p ≤ 0.03) with the increasing urea addition to the diet, with the 10 g urea/kg DM diet resulting in the highest DMI and ADG. The results of this study demonstrated that 10 g urea could substitute 130 g soybean meal per kg feed DM without any adverse effect on growth performance or health in fattening lambs when fed a high concentrate diet.

Insights into the Populations of Proteolytic and Amino Acid-Fermenting Bacteria from Microbiota Analysis Using In Vitro Enrichment Cultures.

This study evaluated the effects of nitrogen source composition and monensin on the populations of proteolytic and amino acid-fermenting bacteria using in vitro enrichment culture. The experiment was designed with a 2 × 2 factorial arrangement: two nitrogen sources, casein (Cas) and tryptone (Try), and two levels of monensin, 0 (C) and 5 µmol/L (M), resulting in four treatments: Cas-C, Cas-M, Try-C, and Try-M. Ruminal fluid collected from three cannulated Holstein dairy cows was used as the inoculum. Each treatment culture was consecutively transferred six times after 24 h of incubation. The results showed that ammonia concentration was lower in Cas than in Try, and it was reduced by monensin addition. In the 6th transfer enrichment cultures, the 16S rRNA gene copy numbers of total bacteria were reduced by monensin but was unaffected by nitrogen sources. Principal component analysis showed that the bacterial communities differed among the treatments. At the genus level, Peptostreptococcus accounted for as much as 41% of the total bacteria in Try-C, but it made up less than 0.02% in the other three treatments. A Pearson correlation analysis showed that the relative abundance of Peptostreptococcus was positively correlated with ammonia concentration. Overall, the results suggest that nitrogen source composition and monensin can affect ruminal ammonia production by modulating the ruminal proteolytic bacterial communities, and some hyper-ammonia-producing bacteria of the genus Peptostreptococcus may be among the main culprits contributing to the high ammonia concentration in the rumen.

Effects of dietary protein sources and nisin on rumen fermentation, nutrient digestion, plasma metabolites, nitrogen utilization, and growth performance in growing lambs.

This study investigated the effects of dietary protein sources and nisin on rumen fermentation, nutrient digestion, plasma metabolites, N utilization, and growth performance in growing lambs. Thirty-two male Hu lambs (23 ± 2 kg initial BW) were assigned to four dietary treatments in a randomized block design with a 2 × 2 factorial arrangement. Two protein sources, soybean meal (SBM) and dried distillers grains with solubles (DDGS), and two levels of nisin, 0 and 30.5 mg of nisin/kg of feed, were used to formulate four isonitrogenous and isoenergetic diets. No interaction (P ≥ 0.16) of protein × nisin was found except on apparent digestibility of DM, OM, NDF, and ADF (P ≤ 0.02). Lambs receiving DDGS had lower (P ≤ 0.04) concentrations of ruminal acetate and butyrate, but propionate concentrations did not differ (P = 0.39), compared with those fed SBM, leading to a trend for reduced total VFA concentration (P = 0.07). Ruminal NH3-N and total branched-chain VFA concentrations were lower (P ≤ 0.01) in the lambs fed DDGS than in those fed SBM. The DDGS-fed lambs had less (P < 0.01) CP, but greater (P < 0.01) ether extract apparent digestibility than those fed SBM. For plasma metabolites, only blood urea N and albumin concentrations were lower in the DDGS-fed lambs (P < 0.01) than in those fed SBM. Nitrogen excretion pathway was altered when DDGS replaced SBM, with fecal N excretion (% of N intake) being greater (P < 0.01), while urinary N excretion (% of N intake) tending to be less (P = 0.06) from the DDGS-fed lambs than those fed SBM. Protein sources affected growth performance in an age/time-dependent manner. From weeks 1 to 4, DDGS resulted in less (P = 0.03) DMI and ADG than SBM. From weeks 5 to 8, DDGS did not affect (P ≥ 0.23) DMI or ADG but resulted in a greater (P = 0.04) G:F than SBM. Final BW did not differ (P = 0.58) duo to protein source. Providing nisin had no impact on DMI (P = 0.44), ADG (P = 0.84), or G:F (P = 0.73). Nisin addition only affected plasma uric acid concentration (P = 0.04). It was concluded that DDGS could substitute for SBM as a nitrogen source to growing Hu lambs to reduce N excretion via urine without adverse effects on animal performance, but nisin supplementation probably had no additional benefits.

Monensin and Nisin Affect Rumen Fermentation and Microbiota Differently In Vitro.

Nisin, a bacteriocin, is a potential alternative to antibiotics to modulate rumen fermentation. However, little is known about its impacts on rumen microbes. This study evaluated the effects of nisin (1 and 5 µM) on in vitro rumen fermentation characteristics, microbiota, and select groups of rumen microbes in comparison with monensin (5 µM), one of the most commonly used ionophores in ruminants. Nisin had greater effects than monensin in inhibiting methane production and decreasing acetate/propionate ratio. Unlike monensin, nisin had no adverse effect on dry matter digestibility. Real-time PCR analysis showed that both monensin and nisin reduced the populations of total bacteria, fungi, and methanogens, while the population of protozoa was reduced only by monensin. Principal component analysis of bacterial 16S rRNA gene amplicons showed a clear separation between the microbiota shaped by monensin and by nisin. Comparative analysis also revealed a significant difference in relative abundance of some bacteria in different taxa between monensin and nisin. The different effects of monensin and nisin on microbial populations and bacterial communities are probably responsible for the discrepancy in their effects on rumen fermentation. Nisin may have advantages over monensin in modulating ruminal microbial ecology and reducing ruminant methane production without adversely affecting feed digestion, and thus it may be used as a potential alternative to monensin fed to ruminants.

[Interaction between microflora and nitrogen nutrients in large intestine and its impacts on host health].

Proteins are not only the main building blocks for the construction of tissue, but also crucial for metabolic activity in animals. The microbial community colonized in the gastrointestinal tract plays an important role in host nutrients metabolism, especially nitrogen nutrients. Bacteria in small intestine could metabolize parts of amino acids (AAs), which further affects the systemic AAs metabolism of host. Compared with that in small intestine, the density of bacteria is much higher and the retention time of chyme is much longer in large intestine. On the one hand, the metabolism and community structure of microflora could be affected by nitrogen nutrients entering the large intestine. Thus, the metabolism of nitrogen nutrients by large intestinal microflora can lead to the formation of several metabolites, which are generally presumed to be detrimental for the host health. This review summarized the effects of dietary protein on the community structure of large intestinal microflora, the microbial metabolites of AAs in large intestine and their impacts on intestinal physiology and host health.

[Effects of nisin on in vitro fermentation, methanogenesis and functional microbial populations of the rumen].

Objective: This study was conducted to evaluate the effects of nisin on in vitro fermentation, methanogenesis and functional microbial populations of the rumen. Methods: The negative control did not contain any additives. Monensin (5 µmol/L) was added as positive control. Nisin was added at 3 doses:3 (NI-3), 9 (NI-9), and 27 mg/100 mL (NI-27). Each treatment contained 4 replicates. Gas and methane production was measured at 0, 3, 6, 9, 12, and 24 h after incubation. Samples of culture were collected at 24 h, and used to measure rumen fermentation parameters and functional microbial populations. Results: Compared with negative control, both nisin and monensin addition dramatically reduced gas and methane production (P<0.05). Nisin addition had no effect on pH, dry matter degradability, and organic matter degradability (P0.05). Ammonia concentration was reduced by NI-9 (P<0.05), but was not influenced by NI-3 and NI-27 (P0.05). In contrast, monensin addition significantly lowered dry matter degradability, organic matter degradability, and ammonia concentration (P<0.05), but had no influence on pH (P0.05). Compared with negative control, both nisin and monensin addition significantly reduced acetate concentration and acetate-propionate ratio (P<0.05), and increased propionate concentration (P<0.05). Quantitative real-time PCR results showed that both nisin and monensin addition had no effects on the populations of total bacteria and Bacteroides (P0.05). Compared with negative control, the populations of protozoa, methanogens, fungi and Firmicutes were not influenced by nisin (P0.05), but were significantly reduced by monensin addition (P<0.05). Both nisin and monensin addition significantly increased the populations of sulfur-reducing bacteria and Clostridium aminophilum (P<0.05), but had no influence on the population of Clostridium sticklandii (P0.05). Conclusion: Appropriate nisin addition could reduce methanogenesis and ammoniagenesis, while had no adverse effect on feed digestion. These effects are probably associated with the variation of rumen functional microbial populations and communities.

[Application of near-infrared spectroscopy to quality detection of milk and its products].

Milk and its products as a kind of ideal comprehensive nutritional food, has becoming an indispensable part of people's daily, life. But at the same time, the quality of dairy products has been also increasingly concerned by consumers. Real-time, rapid and accurate detection of milk and its products in terms of component, adulterants, residues and preservatives is the primary condition for improving the dairy products quality and controlling the production process. Quality predication of milk and its products was often completed by laboratory analysis in the past, which was complicated and time-consuming and could not satisfy the needs for evaluating the milk products quality and monitoring the production proceeding effectively. How to predict the quality of milk and its products quickly and accurately is a practical problem that needs to be resolved. Near-infrared spectroscopy (NIRS) is a rapid, convenient, highly efficient, non-destructive and low-cost analytical technique, which has been widely used in various fields for quantitative and qualitative analysis. As a new analysis technique, NIRS has great potential of application to milk and its products detection, owning to its quick, concise and non--destructive characteristics. The main nutrient components were the major index of milk and its products quality evaluation. Determining the main nutrient components of milk and its products rapidly can provide sound basis for evaluating the products quality. At the same time, adulterants, residues and preservatives were also distinct fingerprint characteristics in the NIR spectra just like the main nutrient components. So this new approaches could also be used in quality distinguishing and on-line detection of milk and its products. Many researches have also concluded that NIRS technology has good stability and high prediction ability on dairy products analysis, exhibites well correlation with the result by labor analysis method. In the present paper, the principles and advantages of NIRS were described. The research advancement of NIRS utilization for milk products nutrient component determination, quality estimation and on-line detection and the application prospect were comprehensively reviewed. With the development of spectral technique, the prediction model gained through NIRS will be more and more reliable and practicable, and the NIRS technique will be more widely used in milk and its products determination, quality estimation and on-line detection.